title: How to store dictionary in HDF5 dataset
body: <p>I have a dictionary, where key is datetime object and value is tuple of integers:</p>
  
  <pre><code>&gt;&gt;&gt; d.items()[0]
  (datetime.datetime(2012, 4, 5, 23, 30), (14, 1014, 6, 3, 0))
  </code></pre>
  
  <p>I want to store it in HDF5 dataset, but if I try to just dump the dictionary h5py raises error:</p>
  
  <blockquote>
    <p>TypeError: Object dtype dtype('object') has no native HDF5 equivalent</p>
  </blockquote>
  
  <p>What would be "the best" way to transform this dictionary so that I can store it in HDF5 dataset?</p>
  
  <p>Specifically I don't want to just dump the dictionary in numpy array, as it would complicate data retrieval based on datetime query. </p>