code: def is_valid(self,
                   value  # type: Any
                   ):
          # type: (...) -> bool
          
          # noinspection PyBroadException
          try:
              # perform validation
              res = self.main_function(value)
  
              # return a boolean indicating if success or failure
              return result_is_success(res)
  
          except Exception:
              # caught exception means failure > return False
              return False
docs: Validates the provided value and returns a boolean indicating success or failure. Any Exception happening in
          the validation process will be silently caught.
  
          :param value: the value to validate
          :return: a boolean flag indicating success or failure