Feature/provenance

Test missing but code can be checked

smash/web/forms/appointment_form.py

@@ -38,9 +38,9 @@ class AppointmentForm(ModelForm):
                 new_value = ','.join([str(element.id) for element in new_value]) #overwrite variable
                 #old value
                 if self.instance.id: #update instance
-                    previous_value = getattr(self.instance, field).all()
-                    old_human_values = '; '.join([str(element) for element in previous_value]) 
-                    previous_value = ','.join([str(element.id) for element in previous_value]) #overwrite variable
+                    list_of_values = getattr(self.instance, field).all()
+                    old_human_values = '; '.join([str(element) for element in list_of_values]) 
+                    previous_value = ','.join([str(element.id) for element in list_of_values]) 
                 else: #new instance
                     old_human_values = ''
                     previous_value = ''