return parsed time to uistome back

tangostationcontrol/configuration/observation_field_settings.py

@@ -48,7 +48,8 @@ class ObservationFieldSettings(_ConfigurationBase):
         """Transparently convert datetime to string in isoformat"""
         if time and not isinstance(time, datetime):
             try:
-                parser.isoparse(time)
+                parsed_time = parser.isoparse(time)
+                return parsed_time.isoformat()
             except ValueError as ex:
                 raise ex
         if time and isinstance(time, datetime):