public function pipe($pipe) 
    {
        if (FALSE === is_callable($pipe)) {
            throw new InvalidArgumentException('pipe should be callable.');
        }

        $this->_pipes[] = $pipe;

        return $this;
    }
public function pipe($pipe) 
    {
        if (FALSE === is_callable($pipe)) {
            throw new InvalidArgumentException('pipe should be callable.');
        }

        $this->_pipes[] = $pipe;

        return $this;
    }
public function pipe ( $ pipe ) { if ( FALSE === is_callable ( $ pipe ) ) { throw new InvalidArgumentException ( 'pipe should be callable.' ) ; } $ this -> _pipes [ ] = $ pipe ; return $ this ; }
set pipes, single mode.

@param $pipe
@return self
@throws \InvalidArgumentException
set pipes single mode .