Update indigo_app/views/documents.py

Co-authored-by: Greg Kempe <greg@kempe.net>

indigo_app/views/documents.py

@@ -131,7 +131,7 @@ def get(self, request, *args, **kwargs):
         document = self.get_object()
         self.eid = self.kwargs.get('eid')
         self.provision_xml = document.get_provision_xml(self.eid)
-        if not self.provision_xml:
+        if self.provision_xml is None:
             messages.error(request, _("No provision with this id found: '%(eid)s'") % {"eid": self.eid})
             return redirect('choose_document_provision', doc_id=document.id)
         return super().get(request, *args, **kwargs)