title: python remove duplicate dictionaries from a list
body: <p>I have a list of dictionaries</p>
  
  <pre><code>l = [
  {'firstname': 'joe', 'surname': 'bloggs'},
  {'firstname': 'john', 'surname': 'smith'},
  {'firstname': 'joe', 'surname': 'bloggs'},
  {'firstname': 'jane', 'surname': 'bloggs'}
  ]
  </code></pre>
  
  <p>how do i remove duplicates i.e. <code>{'firstname': 'joe', 'surname': 'bloggs'}</code> appears twice so would want it only appearing once?</p>