code: def _get_primary_index_in_altered_table(self, diff):
          
          primary_index = {}
  
          for index in self._get_indexes_in_altered_table(diff).values():
              if index.is_primary():
                  primary_index = {index.get_name(): index}
  
          return primary_index
docs: :param diff: The table diff
          :type diff: orator.dbal.table_diff.TableDiff
  
          :rtype: dict