--- a/cubicweb/server/session.py	Fri Apr 05 17:21:14 2019 +0200
+++ b/cubicweb/server/session.py	Fri Apr 05 17:58:19 2019 +0200
@@ -17,16 +17,12 @@
 # with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
 """Repository users' and internal' sessions."""
 
-from __future__ import print_function
-
 import functools
 import sys
 from uuid import uuid4
 from contextlib import contextmanager
 from logging import getLogger
 
-from six import text_type
-
 from logilab.common.registry import objectify_predicate
 
 from cubicweb import QueryError, ProgrammingError, schema, server
@@ -641,7 +637,7 @@
     def transaction_uuid(self, set=True):
         uuid = self.transaction_data.get('tx_uuid')
         if set and uuid is None:
-            self.transaction_data['tx_uuid'] = uuid = text_type(uuid4().hex)
+            self.transaction_data['tx_uuid'] = uuid = uuid4().hex
             self.repo.system_source.start_undoable_transaction(self, uuid)
         return uuid