protected function extendPossibleOptionsWithShortcuts()
	{
		foreach( $this->shortcuts as $short	=> $long )
		{
			if( !isset( $this->possibleOptions[$long] ) )
				throw new InvalidArgumentException( 'Invalid shortcut to not existing option "'.$long.'" .' );
			$this->possibleOptions[$short]	= $this->possibleOptions[$long];
		}
	}