Strict Binary Tree Check

Fizz Buzz Prime Number Fibonacci Number Palindrome Check Even Fibonacci Sum Greatest Common Divisor Package Rice Bags Filter Strings (Java 8 Lambdas and Streams) Comma Separated (Java 8 Lambdas and Streams) Ceasar Cipher Strict Binary Tree Check Two Sum (Pair with a Given Sum)

A binary tree is strict when all nodes have either two or zero child nodes.
Write a method that checks if a binary tree is strict.
TreeNode API methods: node.left() and node.right().

public Boolean isStrictTree(TreeNode node) {

}