title: Discovering keys using h5py in python3
body: <p>In <code>python2.7</code>, I can analyze an <code>hdf5</code> files keys use</p>
  
  <pre><code>$ python
  &gt;&gt;&gt; import h5py
  &gt;&gt;&gt; f = h5py.File('example.h5', 'r')
  &gt;&gt;&gt; f.keys()
  [u'some_key']
  </code></pre>
  
  <p>However, in <code>python3.4</code>, I get something different:</p>
  
  <pre><code>$ python3 -q
  &gt;&gt;&gt; import h5py
  &gt;&gt;&gt; f = h5py.File('example.h5', 'r')
  &gt;&gt;&gt; f.keys()
  KeysViewWithLock(&lt;HDF5 file "example.h5" (mode r)&gt;)
  </code></pre>
  
  <p>What is <code>KeysViewWithLock</code>, and how can I examine my HDF5 keys in Python3?</p>