title: TypeError: argument to reversed() must be a sequence
body: <p>How come enumerate does not produce a sequence?</p>
  
  <pre><code>----&gt; 1 BytesInt('1B')
  
       12 def BytesInt(s):
       13     suffixes = ['B','KB','MB','GB','TB','PB','EB','ZB','YB']
  ---&gt; 14     for power,suffix in reversed(enumerate(suffixes)):
       15         if s.endswith(suffix):
       16             return int(s.rstrip(suffix))*1024**power
  
  TypeError: argument to reversed() must be a sequence
  </code></pre>