code: def get_file_history_2(self, path):
          
          self._get_filectx(path)
          from dulwich.walk import Walker
          include = [self.id]
          walker = Walker(self.repository._repo.object_store, include,
                          paths=[path], max_entries=1)
          return [self.repository.get_changeset(sha)
                  for sha in (x.commit.id for x in walker)]
docs: Returns history of file as reversed list of ``Changeset`` objects for
          which file at given ``path`` has been modified.