human
Solve the following python programming problem given the following code:
def enqueue_edu(self, edu) : 
    destination = edu.destination 
    if (not self.can_send_to (destination)) : 
        return 
deferred = defer.Deferred () 
    self.pending_edus_by_dest.setdefault (destination, []).append ((self, deferred)) 
    def chain(failure) : 
        if (not deferred.called) : 
            deferred.errback (failure) 
def log_failure(f) : 
        logger.warn ('Failed to send edu to %s: %s', destination, f.value) 
deferred.addErrback (log_failure) 
    with PreserveLoggingContext () : 
        self._attempt_new_transaction (destination).addErrback (chain) 
return deferred 

    
    

    Fix the buggy line: self.pending_edus_by_dest.setdefault (destination, []).append ((self, deferred))
assistant
#Here is Python code to fix the buggy line: self.

self.pending_edus_by_dest.setdefault (destination, []).append ((edu, deferred))