docs: def print_alignment(mapping, instance1, instance2):
      """
      print the alignment based on a node mapping
      Args:
          mapping: current node mapping list
          instance1: nodes of AMR 1
          instance2: nodes of AMR 2
  
      """
      result = []
      for instance1_item, m in zip(instance1, mapping):
          r = instance1_item[1] + "(" + instance1_item[2] + ")"
          if m == -1:
              r += "-Null"
          else:
              instance2_item = instance2[m]
              r += "-" + instance2_item[1] + "(" + instance2_item[2] + ")"
          result.append(r)
      return " ".join(result)