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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ls_cmd(argv):
 """List available environments."""

    parser = argparse.ArgumentParser()
    p_group = parser.add_mutually_exclusive_group()
    p_group.add_argument('-b', '--brief', action='store_false')
    p_group.add_argument('-l', '--long', action='store_true')
    args = parser.parse_args(argv)
    lsvirtualenv(args.long)