docs: def detect_missing_relations(self, obj, exc):
          """
          Parse error messages and collect the missing-relationship errors
          as a dict of Resource -> {id set}
          """
          missing = defaultdict(set)
          for name, err in exc.error_dict.items():
              # check if it was a relationship that doesnt exist locally
              pattern = r".+ with id (\d+) does not exist.+"
              m = re.match(pattern, str(err))
              if m:
                  field = obj._meta.get_field(name)
                  res = self.get_resource(field.related_model)
                  missing[res].add(int(m.group(1)))
          return missing