def parseSuffix(self, ref):
        """
        Parse a reference suffix.

        @param ref: The reference of which this suffix is a part.
        @type ref: L{Reference}.
        @raise ConfigFormatError: if a syntax error is found.
        """
        tt = self.token[0]
        if tt == DOT:
            self.match(DOT)
            word = self.match(WORD)
            ref.addElement(DOT, word[1])
        else:
            self.match(LBRACK2)
            tt, tv = self.token
            if [NUMBER, STRING] not in tt:
                raise ConfigFormatError("%s: expected number or string, found %r" % (self.location(), tv))
            self.token = self.getToken()
            tv = eval(tv)
            self.match(RBRACK)
            ref.addElement(LBRACK, tv)
dataset/ETHPy150Open twitterdev/twitter-for-bigquery/libs/config.py/ConfigReader.parseSuffix/swapped operands of `not in`