code: def prt_summary_code(self, prt=sys.stdout):
          
          prt.write('EVIDENCE GROUP AND CODES:\n')
          for grp, c2nt in self.grp2code2nt.items():
              prt.write('    {GRP:19}: {CODES}\n'.format(GRP=grp, CODES=' '.join(c2nt.keys())))
docs: Print summary of codes and groups that can be inputs to get_evcodes.