utils.models.choice module

class utils.models.choice.Annotated(*args, **kwargs)

基类：object

Add context-specific metadata to a type.

Example: Annotated[int, runtime_check.Unsigned] indicates to the hypothetical runtime_check module that this type is an unsigned int. Every other consumer of this type can ignore this metadata and treat this type as int.

The first argument to Annotated must be a valid type.

Details:

• It's an error to call Annotated with less than two arguments.

• Access the metadata via the __metadata__ attribute:

  assert Annotated[int, '$'].__metadata__ == ('$',)
  

• Nested Annotated types are flattened:

  assert Annotated[Annotated[T, Ann1, Ann2], Ann3] == Annotated[T, Ann1, Ann2, Ann3]
  

• Instantiating an annotated type is equivalent to instantiating the

underlying type:

assert Annotated[C, Ann1](5) == C(5)

• Annotated can be used as a generic type alias:

  Optimized: TypeAlias = Annotated[T, runtime.Optimize()]
  assert Optimized[int] == Annotated[int, runtime.Optimize()]
  
  OptimizedList: TypeAlias = Annotated[list[T], runtime.Optimize()]
  assert OptimizedList[int] == Annotated[list[int], runtime.Optimize()]
  

• Annotated cannot be used with an unpacked TypeVarTuple:

  Variadic: TypeAlias = Annotated[*Ts, Ann1]  # NOT valid
  

  This would be equivalent to:

  Annotated[T1, T2, T3, ..., Ann1]
  

  where T1, T2 etc. are TypeVars, which would be invalid, because only one type should be passed to Annotated.

utils.models.choice.choice(value: T, display: Any = None) → T

解决Django Choices拆分实际常量值和展示内容的问题，避免类型检查器判断错误。

用法:

class MyChoices(IntegerChoices):
    CHOICE1 = choice(0, '第一种选择的说明')
    CHOICE2 = choice(1)

尽管允许使用``choice(value)``，仍应手动提供展示内容。