code: def abort(self):
          
          self._coll.chunks.delete_many(
              {"files_id": self._file['_id']}, session=self._session)
          self._coll.files.delete_one(
              {"_id": self._file['_id']}, session=self._session)
          object.__setattr__(self, "_closed", True)
docs: Remove all chunks/files that may have been uploaded and close.