protected function checkSameSlotForKeys(array $keys)
    {
        if (!$count = count($keys)) {
            return false;
        }

        $currentSlot = $this->getSlotByKey($keys[0]);

        for ($i = 1; $i < $count; ++$i) {
            $nextSlot = $this->getSlotByKey($keys[$i]);

            if ($currentSlot !== $nextSlot) {
                return false;
            }

            $currentSlot = $nextSlot;
        }

        return true;
    }