title: subprocess and Type Str doesnt support the buffer API
body: <p>I have</p>
  
  <pre><code>cmd = subprocess.Popen('dir',shell=True,stdout=subprocess.PIPE)
  for line in cmd.stdout:
    columns = line.split(' ')
    print (columns[3])
  </code></pre>
  
  <p>have error in line 3 Type Str doesnt support the buffer API.</p>
  
  <p>What am i doing wrong i am on Python 3.3</p>