code: public function channelGroupGetById($cgid)
      {
          if (!array_key_exists((string)$cgid, $this->channelGroupList())) {
              throw new Ts3Exception("invalid groupID", 0xA00);
          }
  
          return $this->cgroupList[intval((string)$cgid)];
      }
docs: Returns the Channelgroup object matching the given ID.
  
  @param  integer $cgid
  @throws Ts3Exception
  @return Channelgroup