docs: def add_record(self, record):
          """Add or update a given DNS record"""
          rec = self.get_record(record._record_type, record.host)
          if rec:
              rec = record
              for i,r in enumerate(self._entries):
                  if r._record_type == record._record_type \
                          and r.host == record.host:
                              self._entries[i] = record
          else:
              self._entries.append(record)
          self.sort()
          return True