text: FIELD_CACHE = {}
  
  
  def Nullable(cls, **kwargs):
      if cls in FIELD_CACHE:
          return FIELD_CACHE[cls](**kwargs)
  
      class new(cls):
          class Meta:
              name = f"Nullable{cls._meta.name}"
  
          @staticmethod
          def serialize(value):
              if not value:
                  return None
              return cls.serialize(value)
  
          @staticmethod
          def parse_value(value):
              if not value:
                  return ""
              return cls.parse_value(value)
  
      new.__name__ = f"Nullable{type(cls).__name__}"
      new.__doc__ = cls.__doc__
      FIELD_CACHE[cls] = new
      return new(**kwargs)
  