code: def _init_taxid2asscs(self):
          
          taxid2asscs = cx.defaultdict(list)
          for ntanno in self.associations:
              taxid2asscs[ntanno.tax_id].append(ntanno)
          assert len(taxid2asscs) != 0, "**FATAL: NO TAXIDS: {F}".format(F=self.filename)
          # """Print the number of taxids stored."""
          prt = sys.stdout
          num_taxids = len(taxid2asscs)
          prt.write('{N} taxids stored'.format(N=num_taxids))
          if num_taxids < 5:
              prt.write(': {Ts}'.format(Ts=' '.join(sorted(str(t) for t in taxid2asscs))))
          prt.write('\n')
          return dict(taxid2asscs)
docs: Create dict with taxid keys and annotation namedtuple list.