Check if Tree is Binary Search Tree

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Since you already know what a binary search tree is, this challenge will establish how it is you can tell that a tree is a binary search tree or not.

The main distinction of a binary search tree is that the nodes are ordered in an organized fashion. Nodes have at most 2 child nodes (placed to the right and/or left) based on if the child node's value is greater than or equal to (right) or less than (left) the parent node.