def __init__(self, field_name, serializer_field=None, **kwargs):
    super().__init__(**kwargs)
    self.related_field_name = field_name
    self.serializer_field = serializer_field
def __init__(self, field_name, serializer_field=None, **kwargs):
    super().__init__(**kwargs)
    self.related_field_name = field_name
    self.serializer_field = serializer_field