title: Check whether a given value is in a nested dictionary
body: <p>I have this structure, converted using <code>json.load(json)</code></p>
  
  <pre><code>jsonData = [ { 
  thing: [
      name: 'a name',
      keys: [
          key1: 23123,
          key2: 83422
      ]
  thing: [
      name: 'another name',
      keys: [
          key1: 67564,
          key2: 93453
      ]
  etc....
  } ]
  </code></pre>
  
  <p>I have <code>key1check = 67564</code>, 
  I want to check if a thing's key1 matches this value</p>
  
  <pre><code>if key1check in val['thing']['keys']['key1'] for val in jsonData:
      print ('key found, has name of: {}'.format(jsonData['thing']['name'])
  </code></pre>
  
  <p>Should this work?  Is there a better was to do this?</p>