努力合并2本以上的词典

results1()=
{
 "NO4": 
  {
   "type_tests":
    {
     "test1":1.0,
     "test2":5.0,
     "test3":14.0
    }
  },
 "SO3": 
    {
     "type_tests":
    {"test1":1.0,
     "test2":5.0,
     "test3":14.0}
  }
}

results2()=
{
 "CO2": 
  {
   "type_tests":
    {
     "test1":10.0,
     "test2":51.0,
     "test3":34.0
    }
  },
 "H20": 
    {
     "type_tests":
    {"test1":1.0,
     "test2":5.0,
     "test3":14.0}
  }
}

我试着把这篇文章后面的7本词典合并起来:

How to merge two dictionaries in a single expression?

merge_dictionaries={**results1(),**results2(),**results3(),**results4(),**results5(),**results6(),**results7()}
return merge_dictionaries

但是,当我运行合并字典时,它会输出:

TypeError: 'str' object is not a mapping

merging "several" python dictionaries ,我试着:

dicts=[results1(),results2(),results3(),results4(),results5(),results6(),results7()]

for d in dicts:
    for k, v in d.iteritems():
        super_dict[k].add(v)
    return superdict

results7() 字典并保持思考(好像它应该输出其他东西,但没有)

使用这两个字典的所需输出将是合并的字典:

{
"NO4": 
    {
    "type_tests":
        {
         "test1":1.0,
         "test2":5.0,
         "test3":14.0
        }
     },
 "SO3": 
     {
    "type_tests":
        {
         "test1":1.0,
         "test2":5.0,
         "test3":14.0
        }
      },
"CO2": 
      {
     "type_tests":
        {
        "test1":10.0,
        "test2":51.0,
        "test3":34.0
      }
     },
 "H20": 
      {
      "type_tests":
       {
        "test1":1.0,
        "test2":5.0,
        "test3":14.0
    }
  }
}

我怎样才能把这7本字典合并成一本超级字典呢?