--- a/cubicweb/misc/migration/bootstrapmigration_repository.py	Fri Apr 05 17:21:14 2019 +0200
+++ b/cubicweb/misc/migration/bootstrapmigration_repository.py	Fri Apr 05 17:58:19 2019 +0200
@@ -19,11 +19,6 @@
 
 it should only include low level schema changes
 """
-
-from __future__ import print_function
-
-from six import text_type
-
 from cubicweb import ConfigurationError
 from cubicweb.server.session import hooks_control
 from cubicweb.server import schemaserial as ss
@@ -120,7 +115,6 @@
                 default = yams.DATE_FACTORY_MAP[atype](default)
         else:
             assert atype == 'String', atype
-            default = text_type(default)
         return Binary.zpickle(default)
 
     dbh = repo.system_source.dbhelper