Translation can also be delayed for variables that potentially contain translatable objects such as exceptions. Whenever possible translation should not be forced by use of six.text_type() on a message being used with a format string. This patch allows the translation of the translatable replacement text to be delayed until the message is translated. http://docs.openstack.org/developer/oslo.i18n/guidelines.html#avoid-forcing-the-translation-of-translatable-variables Change-Id: I5e259368cbf135116bb3b631835227caa1825894