def get_filtered_copy(self, field_names=None):
    if (not field_names):
        return self.obj_dict
    return {k: copy.deepcopy(self.obj_dict[k]) for k in field_names if (k in self.obj_dict)}
def get_filtered_copy(self, field_names=None):
    if (not field_names):
        return self.obj_dict
    return {k: copy.deepcopy(self.obj_dict[k]) for k in field_names if (k in self.obj_dict)}