public function option($opt)
	{
		$args = \func_get_args();
		if ( \is_array($opt) && isset($opt[0], $this->_defaults[$opt[0]]) ){
			$this->_current_cfg[$opt[0]] = $opt[1];
		}
		else if ( isset($args[0], $args[1], $this->_defaults[$args[0]]) ){
			$this->_current_cfg[$args[0]] = $args[1];
		}
		else{
			throw new InvalidArgumentException('This configuration argument is imaginary... Sorry! :)');
		}
    return $this;
	}