code: public function execute(InputStream $in,OutputStream $out){
  		$operation=$in->getArgument('-o');
  		switch($in->getArgument('-o')){
  			case 'create':
  				$this->createOperation($out);
  			break;
  			case 'upgrade':
  				$this->upgradeOperation($out);
  			break;
  			case 'downgrade':
  				$this->downgradeOperation($out);
  			break;
  			default:
  				throw new OperationNotSupportedException($operation);
  		}
  	}
docs: {@inheritdoc}