def get_last_update(op):
last_update = get_end_time(op)<EOL>if not last_update:<EOL><INDENT>last_event = get_last_event(op)<EOL>if last_event:<EOL><INDENT>last_update = last_event['<STR_LIT>']<EOL><DEDENT><DEDENT>if not last_update:<EOL><INDENT>last_update = get_create_time(op)<EOL><DEDENT>return last_update<EOL>
Return the most recent timestamp in the operation.