title: Check if key is missing after loading json from file in python
body: <p>I'm getting the JSON via:</p>
  
  <pre><code>with open("config.json") as data_file:
      global data
      data = json.load(data_file)
  </code></pre>
  
  <p>And I want to check if the <code>data["example"]</code> is empty or not.</p>