def load_h5py(cls, f, prepend=None):
"""Load object contents from an opened HDF5 file object."""
z = cls(1)
prefix = cls.__name__ + '/'
if prepend is not None:
prefix = prepend + prefix
z.czern = CZern.load_h5py(f, prepend=prepend)
try:
z.Ugrid = f[prefix + 'Ugrid'].value
except ValueError:
pass
try:
z.Vnm = f[prefix + 'Vnm'].value
except ValueError:
pass
try:
z.Cnm = f[prefix + 'Cnm'].value
except ValueError:
pass
return z
