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diff --git a/lib/python3.11/site-packages/flask/scaffold.py b/lib/python3.11/site-packages/flask/scaffold.py
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+++ b/lib/python3.11/site-packages/flask/scaffold.py
@@ -0,0 +1,923 @@
+from __future__ import annotations
+
+import importlib.util
+import os
+import pathlib
+import pkgutil
+import sys
+import typing as t
+from collections import defaultdict
+from datetime import timedelta
+from functools import update_wrapper
+
+from jinja2 import FileSystemLoader
+from werkzeug.exceptions import default_exceptions
+from werkzeug.exceptions import HTTPException
+from werkzeug.utils import cached_property
+
+from . import typing as ft
+from .cli import AppGroup
+from .globals import current_app
+from .helpers import get_root_path
+from .helpers import send_from_directory
+from .templating import _default_template_ctx_processor
+
+if t.TYPE_CHECKING:  # pragma: no cover
+    from .wrappers import Response
+
+# a singleton sentinel value for parameter defaults
+_sentinel = object()
+
+F = t.TypeVar("F", bound=t.Callable[..., t.Any])
+T_after_request = t.TypeVar("T_after_request", bound=ft.AfterRequestCallable)
+T_before_request = t.TypeVar("T_before_request", bound=ft.BeforeRequestCallable)
+T_error_handler = t.TypeVar("T_error_handler", bound=ft.ErrorHandlerCallable)
+T_teardown = t.TypeVar("T_teardown", bound=ft.TeardownCallable)
+T_template_context_processor = t.TypeVar(
+    "T_template_context_processor", bound=ft.TemplateContextProcessorCallable
+)
+T_url_defaults = t.TypeVar("T_url_defaults", bound=ft.URLDefaultCallable)
+T_url_value_preprocessor = t.TypeVar(
+    "T_url_value_preprocessor", bound=ft.URLValuePreprocessorCallable
+)
+T_route = t.TypeVar("T_route", bound=ft.RouteCallable)
+
+
+def setupmethod(f: F) -> F:
+    f_name = f.__name__
+
+    def wrapper_func(self, *args: t.Any, **kwargs: t.Any) -> t.Any:
+        self._check_setup_finished(f_name)
+        return f(self, *args, **kwargs)
+
+    return t.cast(F, update_wrapper(wrapper_func, f))
+
+
+class Scaffold:
+    """Common behavior shared between :class:`~flask.Flask` and
+    :class:`~flask.blueprints.Blueprint`.
+
+    :param import_name: The import name of the module where this object
+        is defined. Usually :attr:`__name__` should be used.
+    :param static_folder: Path to a folder of static files to serve.
+        If this is set, a static route will be added.
+    :param static_url_path: URL prefix for the static route.
+    :param template_folder: Path to a folder containing template files.
+        for rendering. If this is set, a Jinja loader will be added.
+    :param root_path: The path that static, template, and resource files
+        are relative to. Typically not set, it is discovered based on
+        the ``import_name``.
+
+    .. versionadded:: 2.0
+    """
+
+    name: str
+    _static_folder: str | None = None
+    _static_url_path: str | None = None
+
+    def __init__(
+        self,
+        import_name: str,
+        static_folder: str | os.PathLike | None = None,
+        static_url_path: str | None = None,
+        template_folder: str | os.PathLike | None = None,
+        root_path: str | None = None,
+    ):
+        #: The name of the package or module that this object belongs
+        #: to. Do not change this once it is set by the constructor.
+        self.import_name = import_name
+
+        self.static_folder = static_folder  # type: ignore
+        self.static_url_path = static_url_path
+
+        #: The path to the templates folder, relative to
+        #: :attr:`root_path`, to add to the template loader. ``None`` if
+        #: templates should not be added.
+        self.template_folder = template_folder
+
+        if root_path is None:
+            root_path = get_root_path(self.import_name)
+
+        #: Absolute path to the package on the filesystem. Used to look
+        #: up resources contained in the package.
+        self.root_path = root_path
+
+        #: The Click command group for registering CLI commands for this
+        #: object. The commands are available from the ``flask`` command
+        #: once the application has been discovered and blueprints have
+        #: been registered.
+        self.cli = AppGroup()
+
+        #: A dictionary mapping endpoint names to view functions.
+        #:
+        #: To register a view function, use the :meth:`route` decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.view_functions: dict[str, t.Callable] = {}
+
+        #: A data structure of registered error handlers, in the format
+        #: ``{scope: {code: {class: handler}}}``. The ``scope`` key is
+        #: the name of a blueprint the handlers are active for, or
+        #: ``None`` for all requests. The ``code`` key is the HTTP
+        #: status code for ``HTTPException``, or ``None`` for
+        #: other exceptions. The innermost dictionary maps exception
+        #: classes to handler functions.
+        #:
+        #: To register an error handler, use the :meth:`errorhandler`
+        #: decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.error_handler_spec: dict[
+            ft.AppOrBlueprintKey,
+            dict[int | None, dict[type[Exception], ft.ErrorHandlerCallable]],
+        ] = defaultdict(lambda: defaultdict(dict))
+
+        #: A data structure of functions to call at the beginning of
+        #: each request, in the format ``{scope: [functions]}``. The
+        #: ``scope`` key is the name of a blueprint the functions are
+        #: active for, or ``None`` for all requests.
+        #:
+        #: To register a function, use the :meth:`before_request`
+        #: decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.before_request_funcs: dict[
+            ft.AppOrBlueprintKey, list[ft.BeforeRequestCallable]
+        ] = defaultdict(list)
+
+        #: A data structure of functions to call at the end of each
+        #: request, in the format ``{scope: [functions]}``. The
+        #: ``scope`` key is the name of a blueprint the functions are
+        #: active for, or ``None`` for all requests.
+        #:
+        #: To register a function, use the :meth:`after_request`
+        #: decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.after_request_funcs: dict[
+            ft.AppOrBlueprintKey, list[ft.AfterRequestCallable]
+        ] = defaultdict(list)
+
+        #: A data structure of functions to call at the end of each
+        #: request even if an exception is raised, in the format
+        #: ``{scope: [functions]}``. The ``scope`` key is the name of a
+        #: blueprint the functions are active for, or ``None`` for all
+        #: requests.
+        #:
+        #: To register a function, use the :meth:`teardown_request`
+        #: decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.teardown_request_funcs: dict[
+            ft.AppOrBlueprintKey, list[ft.TeardownCallable]
+        ] = defaultdict(list)
+
+        #: A data structure of functions to call to pass extra context
+        #: values when rendering templates, in the format
+        #: ``{scope: [functions]}``. The ``scope`` key is the name of a
+        #: blueprint the functions are active for, or ``None`` for all
+        #: requests.
+        #:
+        #: To register a function, use the :meth:`context_processor`
+        #: decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.template_context_processors: dict[
+            ft.AppOrBlueprintKey, list[ft.TemplateContextProcessorCallable]
+        ] = defaultdict(list, {None: [_default_template_ctx_processor]})
+
+        #: A data structure of functions to call to modify the keyword
+        #: arguments passed to the view function, in the format
+        #: ``{scope: [functions]}``. The ``scope`` key is the name of a
+        #: blueprint the functions are active for, or ``None`` for all
+        #: requests.
+        #:
+        #: To register a function, use the
+        #: :meth:`url_value_preprocessor` decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.url_value_preprocessors: dict[
+            ft.AppOrBlueprintKey,
+            list[ft.URLValuePreprocessorCallable],
+        ] = defaultdict(list)
+
+        #: A data structure of functions to call to modify the keyword
+        #: arguments when generating URLs, in the format
+        #: ``{scope: [functions]}``. The ``scope`` key is the name of a
+        #: blueprint the functions are active for, or ``None`` for all
+        #: requests.
+        #:
+        #: To register a function, use the :meth:`url_defaults`
+        #: decorator.
+        #:
+        #: This data structure is internal. It should not be modified
+        #: directly and its format may change at any time.
+        self.url_default_functions: dict[
+            ft.AppOrBlueprintKey, list[ft.URLDefaultCallable]
+        ] = defaultdict(list)
+
+    def __repr__(self) -> str:
+        return f"<{type(self).__name__} {self.name!r}>"
+
+    def _check_setup_finished(self, f_name: str) -> None:
+        raise NotImplementedError
+
+    @property
+    def static_folder(self) -> str | None:
+        """The absolute path to the configured static folder. ``None``
+        if no static folder is set.
+        """
+        if self._static_folder is not None:
+            return os.path.join(self.root_path, self._static_folder)
+        else:
+            return None
+
+    @static_folder.setter
+    def static_folder(self, value: str | os.PathLike | None) -> None:
+        if value is not None:
+            value = os.fspath(value).rstrip(r"\/")
+
+        self._static_folder = value
+
+    @property
+    def has_static_folder(self) -> bool:
+        """``True`` if :attr:`static_folder` is set.
+
+        .. versionadded:: 0.5
+        """
+        return self.static_folder is not None
+
+    @property
+    def static_url_path(self) -> str | None:
+        """The URL prefix that the static route will be accessible from.
+
+        If it was not configured during init, it is derived from
+        :attr:`static_folder`.
+        """
+        if self._static_url_path is not None:
+            return self._static_url_path
+
+        if self.static_folder is not None:
+            basename = os.path.basename(self.static_folder)
+            return f"/{basename}".rstrip("/")
+
+        return None
+
+    @static_url_path.setter
+    def static_url_path(self, value: str | None) -> None:
+        if value is not None:
+            value = value.rstrip("/")
+
+        self._static_url_path = value
+
+    def get_send_file_max_age(self, filename: str | None) -> int | None:
+        """Used by :func:`send_file` to determine the ``max_age`` cache
+        value for a given file path if it wasn't passed.
+
+        By default, this returns :data:`SEND_FILE_MAX_AGE_DEFAULT` from
+        the configuration of :data:`~flask.current_app`. This defaults
+        to ``None``, which tells the browser to use conditional requests
+        instead of a timed cache, which is usually preferable.
+
+        .. versionchanged:: 2.0
+            The default configuration is ``None`` instead of 12 hours.
+
+        .. versionadded:: 0.9
+        """
+        value = current_app.config["SEND_FILE_MAX_AGE_DEFAULT"]
+
+        if value is None:
+            return None
+
+        if isinstance(value, timedelta):
+            return int(value.total_seconds())
+
+        return value
+
+    def send_static_file(self, filename: str) -> Response:
+        """The view function used to serve files from
+        :attr:`static_folder`. A route is automatically registered for
+        this view at :attr:`static_url_path` if :attr:`static_folder` is
+        set.
+
+        .. versionadded:: 0.5
+        """
+        if not self.has_static_folder:
+            raise RuntimeError("'static_folder' must be set to serve static_files.")
+
+        # send_file only knows to call get_send_file_max_age on the app,
+        # call it here so it works for blueprints too.
+        max_age = self.get_send_file_max_age(filename)
+        return send_from_directory(
+            t.cast(str, self.static_folder), filename, max_age=max_age
+        )
+
+    @cached_property
+    def jinja_loader(self) -> FileSystemLoader | None:
+        """The Jinja loader for this object's templates. By default this
+        is a class :class:`jinja2.loaders.FileSystemLoader` to
+        :attr:`template_folder` if it is set.
+
+        .. versionadded:: 0.5
+        """
+        if self.template_folder is not None:
+            return FileSystemLoader(os.path.join(self.root_path, self.template_folder))
+        else:
+            return None
+
+    def open_resource(self, resource: str, mode: str = "rb") -> t.IO[t.AnyStr]:
+        """Open a resource file relative to :attr:`root_path` for
+        reading.
+
+        For example, if the file ``schema.sql`` is next to the file
+        ``app.py`` where the ``Flask`` app is defined, it can be opened
+        with:
+
+        .. code-block:: python
+
+            with app.open_resource("schema.sql") as f:
+                conn.executescript(f.read())
+
+        :param resource: Path to the resource relative to
+            :attr:`root_path`.
+        :param mode: Open the file in this mode. Only reading is
+            supported, valid values are "r" (or "rt") and "rb".
+        """
+        if mode not in {"r", "rt", "rb"}:
+            raise ValueError("Resources can only be opened for reading.")
+
+        return open(os.path.join(self.root_path, resource), mode)
+
+    def _method_route(
+        self,
+        method: str,
+        rule: str,
+        options: dict,
+    ) -> t.Callable[[T_route], T_route]:
+        if "methods" in options:
+            raise TypeError("Use the 'route' decorator to use the 'methods' argument.")
+
+        return self.route(rule, methods=[method], **options)
+
+    @setupmethod
+    def get(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
+        """Shortcut for :meth:`route` with ``methods=["GET"]``.
+
+        .. versionadded:: 2.0
+        """
+        return self._method_route("GET", rule, options)
+
+    @setupmethod
+    def post(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
+        """Shortcut for :meth:`route` with ``methods=["POST"]``.
+
+        .. versionadded:: 2.0
+        """
+        return self._method_route("POST", rule, options)
+
+    @setupmethod
+    def put(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
+        """Shortcut for :meth:`route` with ``methods=["PUT"]``.
+
+        .. versionadded:: 2.0
+        """
+        return self._method_route("PUT", rule, options)
+
+    @setupmethod
+    def delete(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
+        """Shortcut for :meth:`route` with ``methods=["DELETE"]``.
+
+        .. versionadded:: 2.0
+        """
+        return self._method_route("DELETE", rule, options)
+
+    @setupmethod
+    def patch(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
+        """Shortcut for :meth:`route` with ``methods=["PATCH"]``.
+
+        .. versionadded:: 2.0
+        """
+        return self._method_route("PATCH", rule, options)
+
+    @setupmethod
+    def route(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
+        """Decorate a view function to register it with the given URL
+        rule and options. Calls :meth:`add_url_rule`, which has more
+        details about the implementation.
+
+        .. code-block:: python
+
+            @app.route("/")
+            def index():
+                return "Hello, World!"
+
+        See :ref:`url-route-registrations`.
+
+        The endpoint name for the route defaults to the name of the view
+        function if the ``endpoint`` parameter isn't passed.
+
+        The ``methods`` parameter defaults to ``["GET"]``. ``HEAD`` and
+        ``OPTIONS`` are added automatically.
+
+        :param rule: The URL rule string.
+        :param options: Extra options passed to the
+            :class:`~werkzeug.routing.Rule` object.
+        """
+
+        def decorator(f: T_route) -> T_route:
+            endpoint = options.pop("endpoint", None)
+            self.add_url_rule(rule, endpoint, f, **options)
+            return f
+
+        return decorator
+
+    @setupmethod
+    def add_url_rule(
+        self,
+        rule: str,
+        endpoint: str | None = None,
+        view_func: ft.RouteCallable | None = None,
+        provide_automatic_options: bool | None = None,
+        **options: t.Any,
+    ) -> None:
+        """Register a rule for routing incoming requests and building
+        URLs. The :meth:`route` decorator is a shortcut to call this
+        with the ``view_func`` argument. These are equivalent:
+
+        .. code-block:: python
+
+            @app.route("/")
+            def index():
+                ...
+
+        .. code-block:: python
+
+            def index():
+                ...
+
+            app.add_url_rule("/", view_func=index)
+
+        See :ref:`url-route-registrations`.
+
+        The endpoint name for the route defaults to the name of the view
+        function if the ``endpoint`` parameter isn't passed. An error
+        will be raised if a function has already been registered for the
+        endpoint.
+
+        The ``methods`` parameter defaults to ``["GET"]``. ``HEAD`` is
+        always added automatically, and ``OPTIONS`` is added
+        automatically by default.
+
+        ``view_func`` does not necessarily need to be passed, but if the
+        rule should participate in routing an endpoint name must be
+        associated with a view function at some point with the
+        :meth:`endpoint` decorator.
+
+        .. code-block:: python
+
+            app.add_url_rule("/", endpoint="index")
+
+            @app.endpoint("index")
+            def index():
+                ...
+
+        If ``view_func`` has a ``required_methods`` attribute, those
+        methods are added to the passed and automatic methods. If it
+        has a ``provide_automatic_methods`` attribute, it is used as the
+        default if the parameter is not passed.
+
+        :param rule: The URL rule string.
+        :param endpoint: The endpoint name to associate with the rule
+            and view function. Used when routing and building URLs.
+            Defaults to ``view_func.__name__``.
+        :param view_func: The view function to associate with the
+            endpoint name.
+        :param provide_automatic_options: Add the ``OPTIONS`` method and
+            respond to ``OPTIONS`` requests automatically.
+        :param options: Extra options passed to the
+            :class:`~werkzeug.routing.Rule` object.
+        """
+        raise NotImplementedError
+
+    @setupmethod
+    def endpoint(self, endpoint: str) -> t.Callable[[F], F]:
+        """Decorate a view function to register it for the given
+        endpoint. Used if a rule is added without a ``view_func`` with
+        :meth:`add_url_rule`.
+
+        .. code-block:: python
+
+            app.add_url_rule("/ex", endpoint="example")
+
+            @app.endpoint("example")
+            def example():
+                ...
+
+        :param endpoint: The endpoint name to associate with the view
+            function.
+        """
+
+        def decorator(f: F) -> F:
+            self.view_functions[endpoint] = f
+            return f
+
+        return decorator
+
+    @setupmethod
+    def before_request(self, f: T_before_request) -> T_before_request:
+        """Register a function to run before each request.
+
+        For example, this can be used to open a database connection, or
+        to load the logged in user from the session.
+
+        .. code-block:: python
+
+            @app.before_request
+            def load_user():
+                if "user_id" in session:
+                    g.user = db.session.get(session["user_id"])
+
+        The function will be called without any arguments. If it returns
+        a non-``None`` value, the value is handled as if it was the
+        return value from the view, and further request handling is
+        stopped.
+
+        This is available on both app and blueprint objects. When used on an app, this
+        executes before every request. When used on a blueprint, this executes before
+        every request that the blueprint handles. To register with a blueprint and
+        execute before every request, use :meth:`.Blueprint.before_app_request`.
+        """
+        self.before_request_funcs.setdefault(None, []).append(f)
+        return f
+
+    @setupmethod
+    def after_request(self, f: T_after_request) -> T_after_request:
+        """Register a function to run after each request to this object.
+
+        The function is called with the response object, and must return
+        a response object. This allows the functions to modify or
+        replace the response before it is sent.
+
+        If a function raises an exception, any remaining
+        ``after_request`` functions will not be called. Therefore, this
+        should not be used for actions that must execute, such as to
+        close resources. Use :meth:`teardown_request` for that.
+
+        This is available on both app and blueprint objects. When used on an app, this
+        executes after every request. When used on a blueprint, this executes after
+        every request that the blueprint handles. To register with a blueprint and
+        execute after every request, use :meth:`.Blueprint.after_app_request`.
+        """
+        self.after_request_funcs.setdefault(None, []).append(f)
+        return f
+
+    @setupmethod
+    def teardown_request(self, f: T_teardown) -> T_teardown:
+        """Register a function to be called when the request context is
+        popped. Typically this happens at the end of each request, but
+        contexts may be pushed manually as well during testing.
+
+        .. code-block:: python
+
+            with app.test_request_context():
+                ...
+
+        When the ``with`` block exits (or ``ctx.pop()`` is called), the
+        teardown functions are called just before the request context is
+        made inactive.
+
+        When a teardown function was called because of an unhandled
+        exception it will be passed an error object. If an
+        :meth:`errorhandler` is registered, it will handle the exception
+        and the teardown will not receive it.
+
+        Teardown functions must avoid raising exceptions. If they
+        execute code that might fail they must surround that code with a
+        ``try``/``except`` block and log any errors.
+
+        The return values of teardown functions are ignored.
+
+        This is available on both app and blueprint objects. When used on an app, this
+        executes after every request. When used on a blueprint, this executes after
+        every request that the blueprint handles. To register with a blueprint and
+        execute after every request, use :meth:`.Blueprint.teardown_app_request`.
+        """
+        self.teardown_request_funcs.setdefault(None, []).append(f)
+        return f
+
+    @setupmethod
+    def context_processor(
+        self,
+        f: T_template_context_processor,
+    ) -> T_template_context_processor:
+        """Registers a template context processor function. These functions run before
+        rendering a template. The keys of the returned dict are added as variables
+        available in the template.
+
+        This is available on both app and blueprint objects. When used on an app, this
+        is called for every rendered template. When used on a blueprint, this is called
+        for templates rendered from the blueprint's views. To register with a blueprint
+        and affect every template, use :meth:`.Blueprint.app_context_processor`.
+        """
+        self.template_context_processors[None].append(f)
+        return f
+
+    @setupmethod
+    def url_value_preprocessor(
+        self,
+        f: T_url_value_preprocessor,
+    ) -> T_url_value_preprocessor:
+        """Register a URL value preprocessor function for all view
+        functions in the application. These functions will be called before the
+        :meth:`before_request` functions.
+
+        The function can modify the values captured from the matched url before
+        they are passed to the view. For example, this can be used to pop a
+        common language code value and place it in ``g`` rather than pass it to
+        every view.
+
+        The function is passed the endpoint name and values dict. The return
+        value is ignored.
+
+        This is available on both app and blueprint objects. When used on an app, this
+        is called for every request. When used on a blueprint, this is called for
+        requests that the blueprint handles. To register with a blueprint and affect
+        every request, use :meth:`.Blueprint.app_url_value_preprocessor`.
+        """
+        self.url_value_preprocessors[None].append(f)
+        return f
+
+    @setupmethod
+    def url_defaults(self, f: T_url_defaults) -> T_url_defaults:
+        """Callback function for URL defaults for all view functions of the
+        application.  It's called with the endpoint and values and should
+        update the values passed in place.
+
+        This is available on both app and blueprint objects. When used on an app, this
+        is called for every request. When used on a blueprint, this is called for
+        requests that the blueprint handles. To register with a blueprint and affect
+        every request, use :meth:`.Blueprint.app_url_defaults`.
+        """
+        self.url_default_functions[None].append(f)
+        return f
+
+    @setupmethod
+    def errorhandler(
+        self, code_or_exception: type[Exception] | int
+    ) -> t.Callable[[T_error_handler], T_error_handler]:
+        """Register a function to handle errors by code or exception class.
+
+        A decorator that is used to register a function given an
+        error code.  Example::
+
+            @app.errorhandler(404)
+            def page_not_found(error):
+                return 'This page does not exist', 404
+
+        You can also register handlers for arbitrary exceptions::
+
+            @app.errorhandler(DatabaseError)
+            def special_exception_handler(error):
+                return 'Database connection failed', 500
+
+        This is available on both app and blueprint objects. When used on an app, this
+        can handle errors from every request. When used on a blueprint, this can handle
+        errors from requests that the blueprint handles. To register with a blueprint
+        and affect every request, use :meth:`.Blueprint.app_errorhandler`.
+
+        .. versionadded:: 0.7
+            Use :meth:`register_error_handler` instead of modifying
+            :attr:`error_handler_spec` directly, for application wide error
+            handlers.
+
+        .. versionadded:: 0.7
+           One can now additionally also register custom exception types
+           that do not necessarily have to be a subclass of the
+           :class:`~werkzeug.exceptions.HTTPException` class.
+
+        :param code_or_exception: the code as integer for the handler, or
+                                  an arbitrary exception
+        """
+
+        def decorator(f: T_error_handler) -> T_error_handler:
+            self.register_error_handler(code_or_exception, f)
+            return f
+
+        return decorator
+
+    @setupmethod
+    def register_error_handler(
+        self,
+        code_or_exception: type[Exception] | int,
+        f: ft.ErrorHandlerCallable,
+    ) -> None:
+        """Alternative error attach function to the :meth:`errorhandler`
+        decorator that is more straightforward to use for non decorator
+        usage.
+
+        .. versionadded:: 0.7
+        """
+        exc_class, code = self._get_exc_class_and_code(code_or_exception)
+        self.error_handler_spec[None][code][exc_class] = f
+
+    @staticmethod
+    def _get_exc_class_and_code(
+        exc_class_or_code: type[Exception] | int,
+    ) -> tuple[type[Exception], int | None]:
+        """Get the exception class being handled. For HTTP status codes
+        or ``HTTPException`` subclasses, return both the exception and
+        status code.
+
+        :param exc_class_or_code: Any exception class, or an HTTP status
+            code as an integer.
+        """
+        exc_class: type[Exception]
+
+        if isinstance(exc_class_or_code, int):
+            try:
+                exc_class = default_exceptions[exc_class_or_code]
+            except KeyError:
+                raise ValueError(
+                    f"'{exc_class_or_code}' is not a recognized HTTP"
+                    " error code. Use a subclass of HTTPException with"
+                    " that code instead."
+                ) from None
+        else:
+            exc_class = exc_class_or_code
+
+        if isinstance(exc_class, Exception):
+            raise TypeError(
+                f"{exc_class!r} is an instance, not a class. Handlers"
+                " can only be registered for Exception classes or HTTP"
+                " error codes."
+            )
+
+        if not issubclass(exc_class, Exception):
+            raise ValueError(
+                f"'{exc_class.__name__}' is not a subclass of Exception."
+                " Handlers can only be registered for Exception classes"
+                " or HTTP error codes."
+            )
+
+        if issubclass(exc_class, HTTPException):
+            return exc_class, exc_class.code
+        else:
+            return exc_class, None
+
+
+def _endpoint_from_view_func(view_func: t.Callable) -> str:
+    """Internal helper that returns the default endpoint for a given
+    function.  This always is the function name.
+    """
+    assert view_func is not None, "expected view func if endpoint is not provided."
+    return view_func.__name__
+
+
+def _matching_loader_thinks_module_is_package(loader, mod_name):
+    """Attempt to figure out if the given name is a package or a module.
+
+    :param: loader: The loader that handled the name.
+    :param mod_name: The name of the package or module.
+    """
+    # Use loader.is_package if it's available.
+    if hasattr(loader, "is_package"):
+        return loader.is_package(mod_name)
+
+    cls = type(loader)
+
+    # NamespaceLoader doesn't implement is_package, but all names it
+    # loads must be packages.
+    if cls.__module__ == "_frozen_importlib" and cls.__name__ == "NamespaceLoader":
+        return True
+
+    # Otherwise we need to fail with an error that explains what went
+    # wrong.
+    raise AttributeError(
+        f"'{cls.__name__}.is_package()' must be implemented for PEP 302"
+        f" import hooks."
+    )
+
+
+def _path_is_relative_to(path: pathlib.PurePath, base: str) -> bool:
+    # Path.is_relative_to doesn't exist until Python 3.9
+    try:
+        path.relative_to(base)
+        return True
+    except ValueError:
+        return False
+
+
+def _find_package_path(import_name):
+    """Find the path that contains the package or module."""
+    root_mod_name, _, _ = import_name.partition(".")
+
+    try:
+        root_spec = importlib.util.find_spec(root_mod_name)
+
+        if root_spec is None:
+            raise ValueError("not found")
+    # ImportError: the machinery told us it does not exist
+    # ValueError:
+    #    - the module name was invalid
+    #    - the module name is __main__
+    #    - *we* raised `ValueError` due to `root_spec` being `None`
+    except (ImportError, ValueError):
+        pass  # handled below
+    else:
+        # namespace package
+        if root_spec.origin in {"namespace", None}:
+            package_spec = importlib.util.find_spec(import_name)
+            if package_spec is not None and package_spec.submodule_search_locations:
+                # Pick the path in the namespace that contains the submodule.
+                package_path = pathlib.Path(
+                    os.path.commonpath(package_spec.submodule_search_locations)
+                )
+                search_locations = (
+                    location
+                    for location in root_spec.submodule_search_locations
+                    if _path_is_relative_to(package_path, location)
+                )
+            else:
+                # Pick the first path.
+                search_locations = iter(root_spec.submodule_search_locations)
+            return os.path.dirname(next(search_locations))
+        # a package (with __init__.py)
+        elif root_spec.submodule_search_locations:
+            return os.path.dirname(os.path.dirname(root_spec.origin))
+        # just a normal module
+        else:
+            return os.path.dirname(root_spec.origin)
+
+    # we were unable to find the `package_path` using PEP 451 loaders
+    loader = pkgutil.get_loader(root_mod_name)
+
+    if loader is None or root_mod_name == "__main__":
+        # import name is not found, or interactive/main module
+        return os.getcwd()
+
+    if hasattr(loader, "get_filename"):
+        filename = loader.get_filename(root_mod_name)
+    elif hasattr(loader, "archive"):
+        # zipimporter's loader.archive points to the .egg or .zip file.
+        filename = loader.archive
+    else:
+        # At least one loader is missing both get_filename and archive:
+        # Google App Engine's HardenedModulesHook, use __file__.
+        filename = importlib.import_module(root_mod_name).__file__
+
+    package_path = os.path.abspath(os.path.dirname(filename))
+
+    # If the imported name is a package, filename is currently pointing
+    # to the root of the package, need to get the current directory.
+    if _matching_loader_thinks_module_is_package(loader, root_mod_name):
+        package_path = os.path.dirname(package_path)
+
+    return package_path
+
+
+def find_package(import_name: str):
+    """Find the prefix that a package is installed under, and the path
+    that it would be imported from.
+
+    The prefix is the directory containing the standard directory
+    hierarchy (lib, bin, etc.). If the package is not installed to the
+    system (:attr:`sys.prefix`) or a virtualenv (``site-packages``),
+    ``None`` is returned.
+
+    The path is the entry in :attr:`sys.path` that contains the package
+    for import. If the package is not installed, it's assumed that the
+    package was imported from the current working directory.
+    """
+    package_path = _find_package_path(import_name)
+    py_prefix = os.path.abspath(sys.prefix)
+
+    # installed to the system
+    if _path_is_relative_to(pathlib.PurePath(package_path), py_prefix):
+        return py_prefix, package_path
+
+    site_parent, site_folder = os.path.split(package_path)
+
+    # installed to a virtualenv
+    if site_folder.lower() == "site-packages":
+        parent, folder = os.path.split(site_parent)
+
+        # Windows (prefix/lib/site-packages)
+        if folder.lower() == "lib":
+            return parent, package_path
+
+        # Unix (prefix/lib/pythonX.Y/site-packages)
+        if os.path.basename(parent).lower() == "lib":
+            return os.path.dirname(parent), package_path
+
+        # something else (prefix/site-packages)
+        return site_parent, package_path
+
+    # not installed
+    return None, package_path