title: TypeError: 'str' object does not support item assignment, python with json files
body: <p>The following is my code</p>
  
  <pre><code>import json
  with open('johns.json', 'r') as q:
      l = q.read()
      data = json.loads(l)
      data['john'] = '{}'
      data['john']['user'] = 'hey'
  </code></pre>
  
  <p>The following is the json file</p>
  
  <pre><code>{}
  </code></pre>
  
  <p>Every time I run my code I get the error</p>
  
  <pre><code>    data['john']['user'] = 'hey'
  TypeError: 'str' object does not support item assignment
  </code></pre>
  
  <p>Is there a way to fix this and make data['john']['user'] equal hey?</p>