<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def InitFromGrrMessage(self, message):
 """Init from GrrMessage rdfvalue."""


    if message.source:
      self.client_id = message.source.Basename()
    self.payload_type = compatibility.GetName(message.payload.__class__)
    self.payload = message.payload
    self.timestamp = message.age

    return self