<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_all_tasks(self, subsystem):
 """ Return a generator of all PIDs currently in this cgroup for the given subsystem. """

        with open(os.path.join(self.per_subsystem[subsystem], 'tasks'), 'r') as tasksFile:
            for line in tasksFile:
                yield int(line)