title: Nested dictionary comprehension extracting one key value pair
body: <p>I'm trying to get a single key value pair using dictionary comprehension as an exercise, I have accomplished this using for loops but the best I can do using dictionary comprehension returns an entire dictionary. If I use anything other than 'inner_key01' or 'inner_key02' in the if portion of the below code I get an empty dictionary.</p>
  
  <p>I would like the code to return 'inner_value22'</p>
  
  <pre><code>my_dict = {'inner_key01' :{'inner_key1': 'inner_value1', 'inner_key2': 'inner_value2'},
             'inner_key02' :{'inner_key21': 'inner_value21', 'inner_key22': 'inner_value22'}
  }
  
  next_dict = {inner_key: inner_value for inner_key, inner_value in my_dict.items() for outer_key, outer_value in my_dict.items()if inner_key == 'inner_key02'}
  
  print(next_dict)
  </code></pre>