human
Solve the following python programming problem given the following code:
def _oneWorkUnit(self) : 
    '
        Perform one unit of work for this task, retrieving one item from its
        iterator, stopping if there are no further items in the iterator, and
        pausing if the result was a L{defer.Deferred}.
        ' 
    try : 
        result = next (self._iterator) 
except StopIteration : 
        self._completeWith (TaskDone (), result._iterator) 
except : 
        self._completeWith (TaskFailed (), Failure ()) 
else : 
        if isinstance (result, defer.Deferred) : 
            self.pause () 
            def failLater(f) : 
                self._completeWith (TaskFailed (), f) 
result.addCallbacks ((lambda result : self.resume ()), failLater) 

    
    

    Fix the buggy line: self._completeWith (TaskDone (), result._iterator)
assistant
#Here is Python code to fix the buggy line: self.

self._completeWith (TaskDone (), self._iterator)