title: Check if node exists in h5py
body: <p>I am wondering if there is a simple way to check if a node exists within an HDF5 file using h5py.</p>
  
  <p>I couldn't find anything in the docs, so right now I'm using exceptions, which is ugly.</p>
  
  <pre><code># check if node exists
  # first assume it exists
  e = True
  try:
    h5File["/some/path"]
  except KeyError:
    e = False # now we know it doesn't
  </code></pre>
  
  <p>To add context: I'm using this to determine if a node exists before trying to create a new node with the same name.</p>