@Override
    public boolean containsKey(K key) {
        for (Entry<K, V> entry : this.array) {
            if (entry == null) {
                continue;
            }
            if (entry.next == null) {
                if (entry.key.equals(key)) {
                    return true;
                }
            } else {
                while (entry != null) {
                    if (entry.key.equals(key)) {
                        return true;
                    }
                    entry = entry.next;
                }
            }
        }
        return false;
    }