title: Passing an empty CWD to subprocess
body: <p>.I want to pass cwd into a method that uses subprocess.</p>
  
  <p>Setting a var like this :</p>
  
  <p><code>cwd = kwargs.get('cwd')</code></p>
  
  <p>Then using it later in the method like this :</p>
  
  <pre><code>process = subprocess.Popen(list(command), 
                          shell=False,
                          stdin=subprocess.PIPE,
                          stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE,
                          cwd=cwd)
  </code></pre>
  
  <p>I want to be able to set a default if no kwarg 'cwd' is passed. The purpose is to create clear and simple code, and avoid an if statement.</p>
  
  <p>Without a default in kwargs.get I get an error :</p>
  
  <p><code>[Errno 2] No such file or directory: 'None'</code></p>