human
Complete this python program:
def build_parser():
assistant
#Here is the Python code you requested.

    """Return a parser for parsing requirement lines
    """
    parser = optparse.OptionParser(add_help_option=False)
    option_factories = (SUPPORTED_OPTIONS + SUPPORTED_OPTIONS_REQ)
    for option_factory in option_factories:
        option = option_factory()
        parser.add_option(option)
    def parser_exit(self, msg):
        raise RequirementsFileParseError(msg)
    parser.exit = parser_exit
    return parser