Method for quick testing of a parser against a test string. Good for simple 
           inline microtests of sub expressions while building up larger parser, as in:
           
           expr = Word(nums)
           assert expr.matches("100")
           
           Parameters:
            - testString - string

def matches(self, s, parseAll=True):
        """Method for quick testing of a parser against a test string. Good for simple 
           inline microtests of sub expressions while building up larger parser, as in:
           
           expr = Word(nums)
           assert expr.matches("100")
           
           Parameters:
            - testString - string 
        """
        try:
            self.parseString(_ustr(s), parseAll=parseAll)
            return True
        except ParseBaseException:
            return False