@classmethod
def pre_fork(cls):
    """
        Called only if the --fork argument is used to pre-fork multiple worker processes. In this case, it is called
        by the parent process immediately after signal handlers are set and immediately before the worker sub-processes
        are spawned. It is never called again in the life span of the parent process, even if a worker process crashes
        and gets re-spawned.
        """
