Do not use formlib if you are on Plone5

src/collective/polls/portlet/voteportlet.py

@@ -7,19 +7,25 @@
 from plone.memoize.instance import memoize
 from plone.portlets.interfaces import IPortletDataProvider
 from plone.portlets.interfaces import IPortletManager
+from Products.CMFPlone.utils import getFSVersionTuple
 from Products.Five.browser.pagetemplatefile import ViewPageTemplateFile
 from zope import schema
 from zope.component import ComponentLookupError
 from zope.component import getUtility
 from zope.component import queryUtility
-from zope.formlib import form
 from zope.interface import alsoProvides
 from zope.interface import implementer
 from zope.schema.interfaces import IContextSourceBinder
 from zope.schema.vocabulary import SimpleTerm
 from zope.schema.vocabulary import SimpleVocabulary
 
 
+if getFSVersionTuple()[0] <= 4:
+    from zope.formlib import form
+else:
+    form = None
+
+
 def PossiblePolls(context):
     portal_state = api.content.get_view(
         name='plone_portal_state',
@@ -28,7 +34,11 @@ def PossiblePolls(context):
     )
     utility = queryUtility(IPollUtility, name='collective.polls')
     navigation_root = portal_state.navigation_root()
-    polls = utility.recent_polls(context=navigation_root, show_all=False, limit=999999)
+    polls = utility.recent_polls(
+        context=navigation_root,
+        show_all=False,
+        limit=999999,
+    )
 
     values = [SimpleTerm(value='latest', title=_(u'Latest opened poll'))]
     values.extend(
@@ -148,7 +158,9 @@ class AddForm(base.AddForm):
     """Portlet add form."""
 
     schema = IVotePortlet
-    form_fields = form.Fields(IVotePortlet)
+
+    if form is not None:
+        form_fields = form.Fields(IVotePortlet)
 
     def create(self, data):
         return Assignment(**data)
@@ -158,4 +170,5 @@ class EditForm(base.EditForm):
     """Portlet edit form."""
 
     schema = IVotePortlet
-    form_fields = form.Fields(IVotePortlet)
+    if form is not None:
+        form_fields = form.Fields(IVotePortlet)