IPython.core.ipapi is considered depecrated, and it is not included in several distributions such as Arch Linux, so h5py.enable_ipython_completer() does not work there. It is easily solvable, however, substituting the line:
from IPython.core.ipapi import get as ipget
from IPython import get_ipython as ipget
in h5py/ipy_completer.py inside the source tree.
@ddale, any idea if this is related to the other issue reported on the list?
Fixes issue #410 , IPython.core.ipapi deprecated