def inject_url_defaults(self, endpoint: str, values: dict[str, t.Any]) -> None:
        """Injects the URL defaults for the given endpoint directly into
        the values dictionary passed.  This is used internally and
        automatically called on URL building.

        .. versionadded:: 0.7
        """
        names: t.Iterable[str | None] = (None,)

        # url_for may be called outside a request context, parse the
        # passed endpoint instead of using request.blueprints.
        if "." in endpoint:
            names = chain(
                names, reversed(_split_blueprint_path(endpoint.rpartition(".")[0]))
            )

        for name in names:
            if name in self.url_default_functions:
                for func in self.url_default_functions[name]:
                    func(endpoint, values)
Injects the URL defaults for the given endpoint directly into
        the values dictionary passed.  This is used internally and
        automatically called on URL building.

        .. versionadded:: 0.7
        
src/flask/sansio/app.py