title: Error while trying to list dictionary keys error in python, list object not callable?
body: <pre><code>tel = {'jack':4098, 'sape':4139}
  tel['guido'] = 4127
  list(tel)
  </code></pre>
  
  <hr>
  
  <p>TypeError                                 Traceback (most recent call last)
   in ()
  ----> 1 list(tel)</p>
  
  <p>TypeError: 'list' object is not callable</p>
  
  <p>What am doing wrong? Thanks.</p>