Is ClangBitcodeArgumentListFilter redundant?

[brandb97]

ClangBitcodeArgumentListFilter use its local callback outputFileCallback which does exactly the same thing ArgumentListFilter does.
ClangBitcodeArgumentListFilter's outputFileCallback

def outputFileCallback(self, flag, filename):
        self.outputFilename = filename

ArgumentListFilter's outputFileCallback

def outputFileCallback(self, flag, filename):
        _logger.debug('outputFileCallback: %s %s', flag, filename)
        self.outputFilename = filename