TMSS-745: use safe get

SAS/TMSS/backend/src/tmss/tmssapp/models/specification.py

@@ -228,7 +228,7 @@ class SchedulingUnitObservingStrategyTemplate(NamedVersionedCommon):
         template_doc = deepcopy(self.template)
 
         # loop over all tasks, and add the defaults to each task given the task's specifications_template
-        for task_name, task_doc in list(template_doc['tasks'].items()):
+        for task_name, task_doc in list(template_doc.get('tasks',{}).items()):
             task_specifications_template = TaskTemplate.objects.get(name=task_doc['specifications_template'])
             template_doc['tasks'][task_name] = add_defaults_to_json_object_for_schema(task_doc, task_specifications_template.schema,
                                                                                       cache=TemplateSchemaMixin._schema_cache, max_cache_age=TemplateSchemaMixin._MAX_SCHEMA_CACHE_AGE)
@@ -244,7 +244,7 @@ class SchedulingUnitObservingStrategyTemplate(NamedVersionedCommon):
 
     @property
     def template_doc_with_just_the_parameters(self) -> dict:
-        parameter_pointers = sum([p['refs'] for p in self.template['parameters']], [])
+        parameter_pointers = sum([p['refs'] for p in self.template.get('parameters',[])], [])
 
         template_doc = self.template_doc_complete_with_defaults
         template_doc = subdict_of_pointer_items(template_doc, parameter_pointers)