docs: def _validate_datetime(cls, value):
          """
          validate datetime value
          :param value: datetime value
          :return: None or validators.Invalid or MlbAmException
          """
          datetime_check = validators.Int()
          datetime_check.to_python(value)
          if len(value) != 8:
              raise MlbAmBadParameter("Length Error:{value}({length})".format(value=value, length=len(value)))