title: Add two lists of dictionary without common elements
body: <pre><code>a = [{
          &quot;class&quot;: &quot;class1&quot;,
          &quot;subclass&quot;: &quot;subclass1&quot;
        }]
  
  b = [{
      'class': 'class1',
      'subclass': 'subclass2'
       },
      {
      'class': 'class3',
      'subclass': 'subclass3'
       }]
  
  final_result= [{
          &quot;class&quot;: &quot;class1&quot;,
          &quot;subclass&quot;: &quot;subclass1&quot;
        },
        {
         'class': 'class3',
         'subclass': 'subclass3'
       }]
  </code></pre>
  <p>I want to add list 'b' with 'a' and exclude the element if another element with same class exists in list 'a' as in the above code both lists have a dict with common class - 'class1'</p>