def pytest_fixture_setup(
    fixturedef: FixtureDef[Any], request: SubRequest
) -> object | None:
    """Perform fixture setup execution.

    :param fixturedef:
        The fixture definition object.
    :param request:
        The fixture request object.
    :returns:
        The return value of the call to the fixture function.

    Stops at first non-None result, see :ref:`firstresult`.

    .. note::
        If the fixture function returns None, other implementations of
        this hook function will continue to be called, according to the
        behavior of the :ref:`firstresult` option.

    Use in conftest plugins
    =======================

    Any conftest file can implement this hook. For a given fixture, only
    conftest files in the fixture scope's directory and its parent directories
    are consulted.
    """
Perform fixture setup execution.

    :param fixturedef:
        The fixture definition object.
    :param request:
        The fixture request object.
    :returns:
        The return value of the call to the fixture function.

    Stops at first non-None result, see :ref:`firstresult`.

    .. note::
        If the fixture function returns None, other implementations of
        this hook function will continue to be called, according to the
        behavior of the :ref:`firstresult` option.

    Use in conftest plugins
    =======================

    Any conftest file can implement this hook. For a given fixture, only
    conftest files in the fixture scope's directory and its parent directories
    are consulted.
    
src/_pytest/hookspec.py