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- If the input were {4, 5, -8, 3, 11, -21, 6} the result should be 11
- An empty array should throw an exception
- A single item array should return the single item
- If several numbers are equal and highest, only one should be returned
- If the input were {7, 13} then the result should be 13
- If the input were {13, 4} then the result should be 13