def METHOD_NAME(cls, field: FeatureFlagField):
    """注册额外的FeatureFlagField"""
    name = field.name
    if cls._feature_flag_fields_.get(name, field).label != field.label:
        raise ValueError("Two Feature Flags cannot be set to the same value.")
    if not name:
        raise ValueError("Feature flag's name can not be empty.")
    cls._feature_flag_fields_[name] = field
    setattr(cls, name, field)