How to use the loky.set_loky_pickler function in loky

variables may be set at any time.
    """
    global USE_LOKY
    start_methods = ['fork', 'spawn', 'forkserver']
    if use_loky:
        start_methods.extend(['loky', 'loky_int_main'])
    if start_method is not None:
        if start_method not in start_methods:
            raise ValueError("start_method not in %s" % str(start_methods))
    if use_loky:
        if not _HAS_LOKY:
            raise ImportError("The loky library is not installed.")
        USE_LOKY = True
        loky.backend.context.set_start_method(start_method)
        if loky_pickler is not None:
            loky.set_loky_pickler(loky_pickler)
    else:
        multiprocessing.set_start_method(start_method)