title: subprocess.check_output() module object has out attribute 'check_output'
body: <p>I am playing with the subprocess library. I can perform </p>
  
  <p><code>v = subprocess.check_output("ls")</code></p>
  
  <p>and it works fine. However, when I SSH into a machine and I want to perform a hadoop command, </p>
  
  <p><code>v = subprocess.check_output("hadoop fs -ls /path/to/file* | grep -oE '/(.*)'")</code></p>
  
  <p>I get </p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  AttributeError: 'module' object has no attribute 'check_output'
  </code></pre>
  
  <p>Not quite sure why. I think it might be my lack of understanding of subprocess. How can i fix this error?</p>