docs: def get_new_id(self, relation_name, old_id, strict=False):
      """Given a relation name and its old ID, get the new ID for a relation. If strict is true, an
      error is thrown if no record is found for the relation and old ID.
      """
      record = self.data_access.find(
        "relations as r inner join transfers as t on r.id = t.relation_id",
        (("r.name", relation_name), ("t.old_id", old_id)),
        columns="new_id")
      if record:
        return record[0]
      else:
        if strict:
          raise KeyError("{0} with id {1} not found".format(relation_name, old_id))