@validator('call')
def convert2str(cls, value: Union[(str, Callable)]):
    if callable(value):
        value = f'{value.__module__}:{value.__qualname__}'
    return value
@validator('call')
def convert2str(cls, value: Union[(str, Callable)]):
    if callable(value):
        value = f'{value.__module__}:{value.__qualname__}'
    return value