human
Solve the following python programming problem given the following code:
@ gen_test (timeout = 30) 
def test_parallel_scan(self) : 
    if (not (yield at_least (self.cx, (2, 5, 5)))) : 
        raise SkipTest ('Requires MongoDB >= 2.5.5') 
(yield skip_if_mongos (self.cx)) 
    collection = self.collection 
    (yield collection.remove ()) 
    (yield collection.insert (({ 
        '_id' : i, 
} for i in range (8000)), w = test.env.w)) 
    if test.env.is_replica_set : 
        client = self.motor_rsc () 
        client.read_preference = ReadPreference.SECONDARY 
        collection = client.motor_test.test_collection 
docs = [] 
    @ gen.coroutine 
    def f(cursor) : 
        self.assertTrue (isinstance (cursor, motor.motor_tornado.MotorCommandCursor)) 
        while (yield cursor.fetch_next) : 
            docs.append (cursor.next_object ()) 
cursors = (yield collection.parallel_scan (3)) 
    (yield [f (cursor) for cursor in cursors]) 
    self.assertEqual (len (f), (yield collection.count ())) 

    
    

    Fix the buggy line: self.assertEqual (len (f), (yield collection.count ()))
assistant
#Here is Python code to fix the buggy line: self.

self.assertEqual (len (docs), (yield collection.count ()))