Create a function that returns the majority vote in an array. A majority vote is an element that occurs > N/2 times in an array (where N is the length of the array).

Examples

majority_vote(["A", "A", "B"]) ➞ "A"

majority_vote(["A", "A", "A", "B", "C", "A"]) ➞ "A"

majority_vote(["A", "B", "B", "A", "C", "C"]) ➞ nil

Notes

• The frequency of the majority element must be strictly greater than 1/2.
• If there is no majority element, return nil.
• If the array is empty, return nil.