title: Why does Python's os.walk fail silently?
body: <p>I have the following:</p>
  
  <pre><code>def crawl(rootdir):
      for dir, subdir, files in os.walk(rootdir):
          for file in files:
              print "file found: %s" % file`
  </code></pre>
  
  <p>In my understanding, if I call this on a rootdir that does not exist, I should get an error. instead, it seems to fail quietly. I am a lot less concerned with how to resolve this (although any comments on a pythonic way to do it would help) and way more with understanding why it is happening.</p>