human
Solve the following python programming problem given the following code:
def build_parser() : 
    '
    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 
    return parser 

    
    

    Fix the buggy line: parser.exit = parser
assistant
#Here is Python code to fix the buggy line: parser.

parser.exit = def parser_exit(