#youtube_dl/extractor/youtube.py: The js/swf sig parsers
#ln=\z
    def _parse_sig_js(self, jscode):
        funcname = self._search_regex(
            (r'(["\'])signature\1\s*,\s*(?P<sig>[a-zA-Z0-9$]+)\(',
             r'\.sig\|\|(?P<sig>[a-zA-Z0-9$]+)\('),
            jscode, 'Initial JS player signature function name', group='sig')

        jsi = JSInterpreter(jscode)
        initial_function = jsi.extract_function(funcname)
        return lambda s: initial_function([s])

    def _parse_sig_swf(self, file_contents):
        swfi = SWFInterpreter(file_contents)
        TARGET_CLASSNAME = 'SignatureDecipher'
        searched_class = swfi.extract_class(TARGET_CLASSNAME)
        initial_function = swfi.extract_function(searched_class, 'decipher')
        return lambda s: initial_function([s])