code: def populateFromRow(self, variantSetRecord):
          
          self._created = variantSetRecord.created
          self._updated = variantSetRecord.updated
          self.setAttributesJson(variantSetRecord.attributes)
          self._chromFileMap = {}
          # We can't load directly as we want tuples to be stored
          # rather than lists.
          for key, value in json.loads(variantSetRecord.dataurlindexmap).items():
              self._chromFileMap[key] = tuple(value)
          self._metadata = []
          for jsonDict in json.loads(variantSetRecord.metadata):
              metadata = protocol.fromJson(json.dumps(jsonDict),
                                           protocol.VariantSetMetadata)
              self._metadata.append(metadata)
docs: Populates this VariantSet from the specified DB row.