pydantic递归模型

Question

我正在此另一个 stackoverflow post 库字面要指定字符串的唯一数组以用Pydantic验证数据，但我遇到了一个问题递归地召集另一堂课。

这就是我的代码的样子：

from pydantic import BaseModel, PydanticValueError, ValidationError, validator
from typing import Literal,Optional


ACTION_TYPE_MAPPING = Literal["read", "write", "release"]

OBJECT_TYPE_MAPPING = Literal["multiStateValue", "multiStateInput", "multiStateOutput",
                       "analogValue", "analogInput", "analogOutput",
                       "binaryValue", "binaryInput", "binaryOutput"]

BOOLEAN_ACTION_MAPPING = Literal["active", "inactive"]


# MAIN MODEL
class BacnetRequestModel(BaseModel):
    action_type: ACTION_TYPE_MAPPING
    object_type: OBJECT_TYPE_MAPPING
    object_instance: int
    value: Optional[ValueModel(object_type)]  <---- MESSED UP HERE, how to call ValueModel?


class ValueModel(BaseModel):
    multiStateValue: Optional[int]
    multiStateInput: Optional[int]
    multiStateOutput: Optional[int]
    analogValue: Optional[int]
    analogInput: Optional[int]
    analogOutput: Optional[int]
    binaryValue: Optional[BOOLEAN_ACTION_MAPPING]
    binaryInput: Optional[BOOLEAN_ACTION_MAPPING]
    binaryOutput: Optional[BOOLEAN_ACTION_MAPPING]



test = BacnetRequestModel(action_type="write",
                        object_type="binaryOutput",
                        object_instance="3",
                        value = "active"
                          )

如何根据ObjectType将类 code> valueModel 称为，该功能在这种情况下是binaryOutput < /代码>只能接受boolean_action_mapping的值。任何技巧在这里都没有很多智慧...

追溯是：

    value = Optional[ValueModel(object_type)]
NameError: name 'ValueModel' is not defined