code: def Join(self, Id):
          
          #self._Alter('JOIN_CONFERENCE', Id)
          reply = self._Owner._DoCommand('SET CALL %s JOIN_CONFERENCE %s' % (self.Id, Id),
              'CALL %s CONF_ID' % self.Id)
          return Conference(self._Owner, reply.split()[-1])
docs: Joins with another call to form a conference.
  
          :Parameters:
            Id : int
              Call Id of the other call to join to the conference.
  
          :return: Conference object.
          :rtype: `Conference`