def _serialize(self, value):
        """
        Converts the value to a signed string with timestamp.

        :param value:
            Object to be serialized.

        :returns:
            Serialized value.

        """

        # data = copy.deepcopy(value)
        data = value

        # 1. Serialize
        serialized = pickle.dumps(data).decode('latin-1')

        # 2. Encode
        # Percent encoding produces smaller result then urlsafe base64.
        encoded = parse.quote(serialized, '')

        # 3. Concatenate
        timestamp = str(int(time.time()))
        signature = self._signature(self.name, encoded, timestamp)
        concatenated = '|'.join([encoded, timestamp, signature])

        return concatenated
Converts the value to a signed string with timestamp.

        :param value:
            Object to be serialized.

        :returns:
            Serialized value.