If given node ' s ▁ left ' s right is pointing to given node and its right ' s ▁ left ▁ is ▁ pointing ▁ to ▁ the ▁ node ▁ itself ▁ ▁ then ▁ it ' s a leaf
return node . left and node . left . right == node and node . right and node . right . left == node NEW_LINE