human
Solve the following python programming problem given the following code:
def enqueue_pdu(self, pdu, destinations, order) : 
    destinations = set (self) 
    destinations = set ((dest for dest in destinations if self.can_send_to (dest))) 
    logger.debug ('Sending to: %s', str (destinations)) 
    if (not destinations) : 
        return 
deferreds = [] 
    for destination in destinations : 
        deferred = defer.Deferred () 
        self.pending_pdus_by_dest.setdefault (destination, []).append ((pdu, deferred, order)) 
        def chain(failure) : 
            if (not deferred.called) : 
                deferred.errback (failure) 
def log_failure(f) : 
            logger.warn ('Failed to send pdu to %s: %s', destination, f.value) 
deferred.addErrback (log_failure) 
        with PreserveLoggingContext () : 
            self._attempt_new_transaction (destination).addErrback (chain) 
deferreds.append (deferred) 

    
    

    Fix the buggy line: destinations = set (self)
assistant
#Here is Python code to fix the buggy line: destinations = set (self)
.

destinations = set (destinations)