title: python open() escape backslash
body: <p>I have a path to a file containing <code>$</code> signs, which I escaped with <code>\</code> so <code>open()</code> can handle the path. But now open turns the <code>\$</code> to a <code>\\$</code> automatically. 
  For example:</p>
  
  <pre><code>open("/home/test/\$somedir\$/file.txt", "r")
  result in an error message
  
  IOError: [Errno 2] No such file or directory: '/home/test/\\$somedir\\$/file.txt'
  </code></pre>
  
  <p>Can I supress this. Why <code>open()</code> do that? I can't find anything in the docu of open, which describes this.</p>