<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def main():
 """ Purge a single fastly url """


    parser = OptionParser(description=
             "Purge a single url from fastly.")
    parser.add_option("-k", "--key", dest="apikey",
                      default="", help="fastly api key")
    parser.add_option("-H", "--host", dest="host",
                      help="host to purge from")
    parser.add_option("-p", "--path", dest="path",
                      help="path to purge")

    (options, args) = parser.parse_args()
    for val in options.__dict__.values():
        if val is None:
            print "Missing required options"
            parser.print_help()
            sys.exit(1)

    client = fastly.connect(options.apikey)
    purge = client.purge_url(options.host, options.path)
    print purge