--- a/src/pyams_workflow/interfaces.py	Thu May 23 16:47:00 2019 +0200
+++ b/src/pyams_workflow/interfaces.py	Fri May 24 08:45:15 2019 +0200
@@ -12,21 +12,16 @@
 
 __docformat__ = 'restructuredtext'
 
-
-# import standard library
-
-# import interfaces
-from pyams_utils.interfaces import VIEW_PERMISSION
 from zope.annotation.interfaces import IAttributeAnnotatable
+from zope.interface import Attribute, Interface, Invalid, implementer, invariant
 from zope.interface.interfaces import IObjectEvent, ObjectEvent
+from zope.lifecycleevent import ObjectCreatedEvent
 from zope.lifecycleevent.interfaces import IObjectCreatedEvent
+from zope.schema import Bool, Choice, Datetime, Int, List, Object, Set, Text, TextLine
+from zope.schema.vocabulary import SimpleTerm, SimpleVocabulary
 
-# import packages
 from pyams_security.schema import Principal
-from zope.interface import implementer, invariant, Interface, Attribute, Invalid
-from zope.lifecycleevent import ObjectCreatedEvent
-from zope.schema import Choice, Datetime, Set, TextLine, Text, List, Object, Int, Bool
-from zope.schema.vocabulary import SimpleVocabulary, SimpleTerm
+from pyams_utils.interfaces import VIEW_PERMISSION
 
 from pyams_workflow import _
 
@@ -201,6 +196,9 @@
         """Get transition with transition_id"""
 
 
+WORKFLOWS_VOCABULARY = 'PyAMS workflows'
+
+
 class IWorkflowInfo(Interface):
     """Get workflow info about workflowed object, and drive workflow.
 
@@ -373,7 +371,7 @@
     workflow_name = Choice(title=_("Workflow name"),
                            description=_("Name of workflow utility managing this content"),
                            required=True,
-                           vocabulary='PyAMS workflows')
+                           vocabulary=WORKFLOWS_VOCABULARY)
 
     view_permission = Choice(title=_("View permission"),
                              description=_("This permission will be required to display content"),