code: def _filter_rows(self, rows):
          
          filtered_rows = []
          for row in rows:
              filtered_row = []
              for idx, name in enumerate(self.columns.keys()):
                  if name in self.visible_columns:
                      filtered_row.append(row[idx])
              filtered_rows.append(filtered_row)
          return filtered_rows
docs: Filter `rows` based on the visible columns.