public function action(callable $action = null)
    {
        if (\func_num_args() === 0) {
            return $this->_action;
        }

        $this->_action = $action;

        return $this;
    }
public function action(callable $action = null)
    {
        if (\func_num_args() === 0) {
            return $this->_action;
        }

        $this->_action = $action;

        return $this;
    }
public function action ( callable $ action = null ) { if ( \ func_num_args ( ) === 0 ) { return $ this -> _action ; } $ this -> _action = $ action ; return $ this ; }
Get or set command action.

@param callable|null $action If provided it is set

@return callable|self If $action provided then self, otherwise the preset action.
Get or set command action .