code: public function serverGroupDelete($sgid, $force = false)
      {
          $this->serverGroupListReset();
  
          $this->execute("servergroupdel", array("sgid" => $sgid, "force" => $force));
      }
docs: Deletes the server group specified with $sgid. If $force is set to 1, the server group
  will be deleted even if there are clients within.
  
  @param  integer $sgid
  @param  boolean $force
  @return void