argparse exception

# --checkers checkers (--url URL --project Prj [--dump]) | (--mergeInput input.txt [--removeDisabled])
if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(
        description="Sets the checkers of a klocwork project")
    mutexGroup = parser.add_mutually_exclusive_group(required=True)
    serverGroup = mutexGroup.add_argument_group('serverGroup')
    serverGroup.add_argument("-u", "--url", action="store", required=True, help="klocwork server URL.")
    serverGroup.add_argument("-p", "--project", action="store", required=True, help="klocwork project name.")
    serverGroup.add_argument("--dump", action="store_true", required=False, help="Dump the current checkers config.")
    mergeGroup = mutexGroup.add_argument_group('mergeGroup')
    mergeGroup.add_argument(
        "--mergeInput", action="store", required=True,
        help="Input file to merge for the '--checkers' file. Format: checkerName Enabled|Disabled")
    mergeGroup.add_argument(
        "--removeDisabled", action="store_true", required=False,
        help="Disabled checkers will be removed from the '--checkers' file.")
    parser.add_argument(
        "-c", "--checkers", action="store", required=True, help="File which lists the checkers to be enabled.")

    args = parser.parse_args()