def METHOD_NAME(key, go_tags):
  """Check that for given yaml key from configuration file exists a corresponding yaml tag of some field in a Go struct."""
  for file, tags in go_tags.items():
    if key in tags:
      if args.verbose:
        print("key {} found in {}".format(key, file))
      return True
  print("ERROR: key {} does not exist in any .go file".format(key), file=sys.stderr)
  return False