Rethinking BST `Find` method signature

[pypkaed]

Describe the bug
The Find method in BinarySearchTree throws exceptions. Semantically, 'Find' and 'Get' are two different methods. My suggestion is to return null in case nothing is found in 'Find' and throw exceptions in a new method 'Get'. I understand that there would be a backwards compatibility issue, but the current state really limits the usage of the method and is unintuitive to use.

[github-actions]

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