def _get_config(self, unit, filename):
        """Get a ConfigParser object for parsing a unit's config file."""
        file_contents = unit.file_contents(filename)

        # NOTE(beisner):  by default, ConfigParser does not handle options
        # with no value, such as the flags used in the mysql my.cnf file.
        # https://bugs.python.org/issue7005
        config = configparser.ConfigParser(allow_no_value=True)
        config.readfp(io.StringIO(file_contents))
        return config
Get a ConfigParser object for parsing a unit's config file.