title: Why python overwrites key value pair
body: <p>I am adding dictionary in list but after addition all the dictionary have the same values. What is wrong in the below code</p>
  
  <pre><code>final_data=[]
  print(type(final_data))
  thisdict =  {
    "brand": "Ford",
    "model": "Mustang",
    "year": 1964
  }
  
  thisdict["year"] = 2018
  final_data.append(thisdict)
  thisdict["year"]=2019
  final_data.append(thisdict)
  
  print(final_data)
  </code></pre>
  
  <p>In final_data there are two dictionary pair but 2018 is no where visible. Both dictionary have the 2019 values.</p>
  
  <p>This is what I actually want in my code</p>
  
  <pre><code>qs=Member.objects.all()
  for elem in qs:
      for v in elem:
          final_data.append(
              {"field_name": v, "field_type": Member._meta.get_field(v).get_internal_type()})
  </code></pre>
  
  <p>I am not able to get the field_data which queryset qs have.</p>