code: def verify(
              self, headers, serialized_request_env, deserialized_request_env):
          # type: (Dict[str, Any], str, RequestEnvelope) -> None
          
          local_now = datetime.now(tz.tzutc())
          request_timestamp = deserialized_request_env.request.timestamp
          if (abs((local_now - request_timestamp).seconds) >
                  (self._tolerance_in_millis / 1000)):
              raise VerificationException("Timestamp verification failed")
docs: Verify if the input request timestamp is in tolerated limits.
  
          The verify method retrieves the request timestamp and check if
          it falls in the limit set by the tolerance, by checking with
          the current timestamp in UTC.
  
          :param headers: headers of the input POST request
          :type headers: Dict[str, Any]
          :param serialized_request_env: raw request envelope in the
              input POST request
          :type serialized_request_env: str
          :param deserialized_request_env: deserialized request envelope
              instance of the input POST request
          :type deserialized_request_env:
              :py:class:`ask_sdk_model.request_envelope.RequestEnvelope`
          :raises: :py:class:`VerificationException` if difference between
              local timestamp and input request timestamp is more than
              specific tolerance limit