fixup! XMLExportImport: WIP support pickle protocol 3 🚧

product/ERP5/Document/BusinessTemplate.py

@@ -78,7 +78,8 @@ from OFS.Traversable import NotFound
 from OFS import SimpleItem
 from OFS.Image import Pdata
 import coverage
-from io import BytesIO, StringIO
+from io import BytesIO
+from six.moves import StringIO
 from copy import deepcopy
 from zExceptions import BadRequest
 from Products.ERP5Type.XMLExportImport import exportXML, customImporters
@@ -1084,8 +1085,8 @@ class ObjectTemplateItem(BaseTemplateItem):
     for path, old_object in upgrade_list:
       # compare object to see it there is changes
       new_object = self._objects[path]
-      new_io = BytesIO()
-      old_io = BytesIO()
+      new_io = StringIO()
+      old_io = StringIO()
       exportXML(new_object._p_jar, new_object._p_oid, new_io)
       new_obj_xml = new_io.getvalue()
       try: