title: usage of "dict_value" and "dict_key" in python3
body: <p><code>dict = {'a':1, 'b':2}</code></p>
  
  <p><code>dict.keys</code> gives <code>dict_keys(['a', 'b'])</code></p>
  
  <p><code>dict.values</code> gives <code>dict_values([1, 2])</code>.</p>
  
  <p>Can someone give examples how <code>dict_keys</code> and <code>dict_values</code> come handy? Why dictionary returns these types instead of just returning a list?</p>
  
  <p>I often do <code>list(dict.keys)</code> and <code>list(dict.values)</code>, converting into a list to loop over. </p>