<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _StructMessageToJsonObject(self, message):
 """Converts Struct message according to Proto3 JSON Specification."""

    fields = message.fields
    ret = {}
    for key in fields:
      ret[key] = self._ValueMessageToJsonObject(fields[key])
    return ret