Defines a pattern that can span multiple styles.
        
        :param      style        | <XCodeHighlighter.Style>
                    openPattern  | <str>
                    closePattern | <str>

def defineMultiline(self, style, openPattern, closePattern):
        """
        Defines a pattern that can span multiple styles.
        
        :param      style        | <XCodeHighlighter.Style>
                    openPattern  | <str>
                    closePattern | <str>
        """
        self._multiline.append((style, openPattern, closePattern))