<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def nonull_dict(self):
 """Like dict, but does not hold any null values. :return: """

        return {k: v for k, v in six.iteritems(self.dict) if v and k != '_codes'}