human
Solve the following python programming problem given the following code:
def _make_time_sort_key(container_to_attempt_id = None) : 
    'Sort key to sort the given dictionaries containing IDs roughly by time
    (earliest first).

    We consider higher attempt_nums "later" than higher task_nums (of the
    same step type) because fatal errors usually occur on the final
    attempt of a task.

    If we can, we convert (YARN) container IDs to attempt IDs. Unconverted
    container IDs are considered more "recent" than any task/attempt ID
    (these usually come from task logs).
    ' 
    container_to_attempt_id = (container_to_attempt_id or { 
        
}) 
    def sort_key(d) : 
        container_id = (d.get ('container_id') or '') 
        inferred_attempt_id = (container_to_attempt_id.get (container_id) or '') 
        if inferred_attempt_id : 
            container_id = '' 
attempt_parts = (d.get ('attempt_id') or inferred_attempt_id or d.get ('task_id') or d.get ('job_id') or d.get ('application_id') or _to_job_id (container_id) or '').split ('_') 
        timestamp_and_step = '_'.join (attempt_parts [1 : 3]) 
        task_type = '_'.join (attempt_parts [3 : 4]) 
        task_num = '_'.join (attempt_parts [4 : 5]) 
        attempt_num = '_'.join (attempt_parts [5 : 6]) 
        return (timestamp_and_step, container_id, task_type, attempt_num, task_num) 
return container_to_attempt_id 

    
    

    Fix the buggy line: return container_to_attempt_id
assistant
#Here is Python code to fix the buggy line: return container_to_attempt_id
.

return def sort_key(