public function setMode($mode)
    {
        $this->mode = (null === $mode ? null : (bool) $mode);
        return $this;
    }
public function setMode($mode)
    {
        $this->mode = (null === $mode ? null : (bool) $mode);
        return $this;
    }
public function setMode ( $ mode ) { $ this -> mode = ( null === $ mode ? null : ( bool ) $ mode ) ; return $ this ; }
Debugger mode, production or development.

@param bool|null $mode
@return $this
Debugger mode production or development .