<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def created(self):
 """Datetime at which the job was created. :rtype: ``datetime.datetime``, or ``NoneType`` :returns: the creation time (None until set from the server). """

        statistics = self._properties.get("statistics")
        if statistics is not None:
            millis = statistics.get("creationTime")
            if millis is not None:
                return _helpers._datetime_from_microseconds(millis * 1000.0)