def _format_option_strings(self, option, mvarfmt=' <%s>', optsep=', '):
        """
        Return a comma-separated list of option strings and metavars.

        :param option:  tuple of (short opt, long opt), e.g: ('-f', '--format')
        :param mvarfmt: metavar format string - evaluated as mvarfmt % metavar
        :param optsep:  separator
        """
        opts = []

        if option._short_opts:
            opts.append(option._short_opts[0])
        if option._long_opts:
            opts.append(option._long_opts[0])
        if len(opts) > 1:
            opts.insert(1, optsep)

        if option.takes_value():
            metavar = option.metavar or option.dest.lower()
            opts.append(mvarfmt % metavar.lower())

        return ''.join(opts)
dataset/ETHPy150Open anzev/hedwig/build/pip/pip/baseparser.py/PrettyHelpFormatter._format_option_strings/original