docs: def main():
      """Read configuration and execute test runs."""
      parser = argparse.ArgumentParser(description='Stress test applications.')
      parser.add_argument('config_path', help='Path to configuration file.')
      args = parser.parse_args()
      try:
          configuration = load_configuration(args.config_path)
      except InvalidConfigurationError:
          print("\nConfiguration is not valid.")
          print('Example:\n{}'.format(help_configuration))
          return 1
      print("Starting up ...")
      futures = []
      with ProcessPoolExecutor(configuration[PROCESSORS]) as executor:
          for _ in range(configuration[PROCESSES]):
              futures.append(executor.submit(execute_test, configuration))
      print("... finished")
      test_stats = combine_test_stats([f.result() for f in futures])
      show_test_stats(test_stats)
      return 0