title: Python - dump dict as a json string
body: <p>What am I missing?  I want to dump a dictionary as a json string.</p>
  
  <p>I am using python 2.7</p>
  
  <p>With this code:</p>
  
  <pre><code>import json
  fu = {'a':'b'}
  output = json.dump(fu)
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/usr/local/lib/python2.7/dist-packages/gevent-1.0b2-py2.7-linux-x86_64.egg/gevent/greenlet.py", line 328, in run
      result = self._run(*self.args, **self.kwargs)
    File "/home/ubuntu/workspace/bitmagister-api/mab.py", line 117, in mabLoop
      output = json.dump(fu)
  TypeError: dump() takes at least 2 arguments (1 given)
  &lt;Greenlet at 0x7f4f3d6eec30: mabLoop&gt; failed with TypeError
  </code></pre>