code: def map_statements(self):
          for stmt in self.statements:
              for agent in stmt.agent_list():
                  if agent is None:
                      continue
                  all_mappings = []
                  for db_name, db_id in agent.db_refs.items():
                      if isinstance(db_id, list):
                          db_id = db_id[0][0]
                      mappings = self._map_id(db_name, db_id)
                      all_mappings += mappings
                  for map_db_name, map_db_id, score, orig_db_name in all_mappings:
                      if map_db_name in agent.db_refs:
                          continue
                      if self.scored:
                          try:
                              orig_score = agent.db_refs[orig_db_name][0][1]
                          except Exception:
                              orig_score = 1.0
                          agent.db_refs[map_db_name] = \
                              [(map_db_id, score * orig_score)]
                      else:
                          if map_db_name in ('UN', 'HUME'):
                              agent.db_refs[map_db_name] = [(map_db_id, 1.0)]
                          else:
                              agent.db_refs[map_db_name] = map_db_id