code: def warn_prefix_values(trie):
      '''
      Prints warning messages for every node that has both a value and a
      longest_prefix.
      '''
      for current, _parent in trie.dfs():
          if current.has_value and current.longest_prefix is not None:
              LOGGER.warn(('pattern {} (value {}) is a superstring of pattern '
                           '{} (value {}) and will never be matched').format(
                               current.prefix, current.value,
                               current.longest_prefix.prefix, current.longest_prefix.value)f warn_prefix_values(trie):
      '''
      Prints warning messages for every node that has both a value and a
      longest_prefix.
      '''
      for current, _parent in trie.dfs():
          if current.has_value and current.longest_prefix is not None:
              LOGGER.warn(('pattern {} (value {}) is a superstring of pattern '
                           '{} (value {}) and will never be matched').format(
                               current.prefix, current.value,
                               current.longest_prefix.prefix, current.longest_prefix.value))
docs: Prints warning messages for every node that has both a value and a
      longest_prefix.