jsontoh5.py fails on converting json file

Hello, 
I'm converting an hdf5 file produced by keras to json which works fine.
However, upon converting back from this json file to hdf5 I am running into errors with a call within h5json/hdf5db.py, in the function toRef(....)
In Line 1745, in toRef, for item in data: 
Nonetype object is not iterable.

Is there a current issue in handling hdf5 files generated by Keras?