title: Python and dictionary like object
body: <p>I need a python 3.1 deep update function for dictionaries (a function that will recursively update child dictionaries that are inside a parent dictionary).</p>
  
  <p>But I think, in the future, my function could have to deal with objects that behave like dictionaries but aren't. And furthermore I want to avoid using <strong><code>isinstance</code></strong> and <strong><code>type</code></strong> (because they are considered bad, as I can read on almost every Pythonista's blog).</p>
  
  <p>But duck typing is part of Python's philosophy, so how could I check if an object is dictionary-like?</p>
  
  <p>Thanks!</p>
  
  <p>Edit : Thank all for the answers. Just in case, the function I coded can be found at this place : <a href="http://blog.cafeaumiel.com/public/python/dict_deep_update.py" rel="noreferrer">http://blog.cafeaumiel.com/public/python/dict_deep_update.py</a></p>