@pimms.param<EOL><INDENT>def hemis(h):<DEDENT>
if   h is None:        return pyr.m()<EOL>elif pimms.is_pmap(h): return h<EOL>elif pimms.is_map(h):  return pyr.pmap(h)<EOL>else: raise ValueError('<STR_LIT>')<EOL>
sub.hemis is a persistent map of hemisphere names ('lh', 'rh', possibly others) for the
given subject sub.