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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 main(argv):
 """Play matches between two neural nets."""

    _, black_model, white_model = argv
    utils.ensure_dir_exists(FLAGS.eval_sgf_dir)
    play_match(black_model, white_model, FLAGS.num_evaluation_games, FLAGS.eval_sgf_dir)