FIX: remove `base.MappingHDF5` from class definition, resolves https://github.com/h5py/h5py/issues/744
FIX: remove `base.MappingHDF5` from class definition, resolves https://github.com/h5py/h5py/issues/744

h5py/h5py,h5py/h5py,h5py/h5py