title: How to perform Intersection with custom property in python
body: <pre><code>class Random:
      def __init__(self,id):
          self.id=id
          self.prop=None
  
  list_1={Random(12), Random(15), Random(22)}
  list_2={Random(22),Random(9),Random(88)}
  list_3={Random(88),Random(22),Random(12)}
  
  result=list_1.intersection(list_2).intersection(list_3)
  print (list(result))
  
  #expected result = Random Object containing id=22
  #returned result =[]
  </code></pre>
  
  <p>How to custom intersect among lists with custom field - id in the above case ?</p>