def pytest_collectstart(collector: Collector) -> None:
    """Collector starts collecting.

    :param collector:
        The collector.

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

    Any conftest file can implement this hook. For a given collector, only
    conftest files in the collector's directory and its parent directories are
    consulted.
    """
Collector starts collecting.

    :param collector:
        The collector.

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

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