code: protected final void merge(final InternalNode<K, V> nodeParent, final int slot, final Node<K, V> nodeFROMx) {
  		final InternalNode<K, V> nodeFROM = (InternalNode<K, V>) nodeFROMx;
  		final InternalNode<K, V> nodeTO = this;
  		final int sizeTO = nodeTO.allocated;
  		final int sizeFROM = nodeFROM.allocated;
  		// copy keys from nodeFROM to nodeTO
  		System.arraycopy(nodeFROM.keys, 0, nodeTO.keys, sizeTO + 1, sizeFROM);
  		System.arraycopy(nodeFROM.childs, 0, nodeTO.childs, sizeTO + 1, sizeFROM + 1);
  		// add key to nodeTO
  		nodeTO.keys[sizeTO] = nodeParent.keys[slot];
  		nodeTO.allocated += sizeFROM + 1; // keys of FROM and key of nodeParent
  		// remove key from nodeParent
  		nodeParent.remove(slot);
  		// Free nodeFROM
  		tree.freeNode(nodeFROM);
  	}
docs: ========= Remove Helpers =========