Issue #273 message in case there are no appointment types set

smash/web/api_views/subject.py

@@ -356,7 +356,7 @@ def serialize_subject(study_subject):
         
         appointment_types = ['{} ({})'.format(at.code, at.description) for at in visit.appointment_types.all()]
         if len(appointment_types) == 0:
-            appointment_types = 'No appointment types set.'
+            appointment_types = ['No appointment types set.']
 
         serialized_visits.append({
             "status": status,