Is there a way to get all the names that are currently associated with an opened HDF5 file?
This is related to the closing of HDFStore stores: <a href="https://github.com/pydata/pandas/issues/4409"> API: HDFStore closing is buggy #4409 </a>, from which I understand that it is possible to have multiple open stores pointing to the same file, and that closing one of the stores does not close all the others, so one can still put things in others.

But what happens if I start off with the following in a session

<pre><code>df = pd.DataFrame(np.arange(10))

store1 = pd.HDFStore('test.h5')    
store2 = pd.HDFStore('test.h5')    
some_unmemorable_name = pd.HDFStore('test.h5')    
</code></pre>


and I do some stuff with these stores, such as

<pre><code>store1.append('df1', df)
store2.append('df2',  df)

store1.close()
store2.close()
</code></pre>


then, I spend some time doing a bunch of stuff unrelated to the stores, after which I want to save stuff to 'test.h5' again but to overwrite if it's already there.   At this point, I have already forgotten about not having closed <code>some_unmemorable_name</code>.  If I open the file with <code>mode = 'w'</code> now, 

<pre><code>In [63]: store = pd.HDFStore('test.h5', mode = 'w')
/nuwa_cluster/opt/anaconda3-2.0.1/lib/python3.4/site-packages/tables/file.py in open_file(filename, mode, title, root_uep, filters, **kwargs)
    313                 raise ValueError(
    314                     "The file '%s' is already opened.  Please "
--> 315                     "close it before reopening in write mode." % filename)
    316 
    317     # Finally, create the File instance, and return it

ValueError: The file 'test.h5' is already opened.  Please close it before reopening in write mode.
</pre></code>

and there is no way to close the opened store because it was opened so long ago that I cannot recall its name.   Deleting the file doesn't help because the current session is still 'aware' of the opened store.  Restarting the session means that everything will have to be done again.  If there is way to be able to get the names of all currently opened stores, then they can all be closed.  
