Retrieve the timestamp at which the task was enqueued.

        See: https://cloud.google.com/appengine/docs/python/taskqueue/rest/tasks

        :rtype: :class:`datetime.datetime` or ``NoneType``
        :returns: Datetime object parsed from microsecond timestamp, or
                  ``None`` if the property is not set locally.

def time_enqueued(self):
        """Retrieve the timestamp at which the task was enqueued.

        See: https://cloud.google.com/appengine/docs/python/taskqueue/rest/tasks

        :rtype: :class:`datetime.datetime` or ``NoneType``
        :returns: Datetime object parsed from microsecond timestamp, or
                  ``None`` if the property is not set locally.
        """
        value = self._properties.get('enqueueTimestamp')
        if value is not None:
            return _datetime_from_microseconds(int(value))