title: Error opening file in H5PY (File signature not found)
body: <p>I've been using the following bit of code to open some HDF5 files, produced in MATLAB, in python using H5PY:</p>
  
  <pre><code>import h5py as h5
  data='dataset.mat'
  f=h5.File(data, 'r')
  </code></pre>
  
  <p>However I'm getting the following error:</p>
  
  <pre><code>OSError: Unable to open file (File signature not found)
  </code></pre>
  
  <p>I've checked that the files that I'm trying to open are version 7.3 MAT-files and are HDF5 format.  In fact I've used H5PY to open the same files successfully before.  I've confirmed that the files exist and are accessible so I'm not really sure where the error is coming from.  Any advice would be greatly appreciated, thanks in advance : )</p>