-----Description-----
This task requires writing a Lean 4 method that returns the majority element from a list of integers.

The majority element is the one that appears more than ⌊n / 2⌋ times in the list, where n is the list's length. You may assume that a majority element always exists in the input.

-----Input-----
- nums: A list of integers (with at least one majority element).

-----Output-----
Returns the majority element — the value that appears more than ⌊n / 2⌋ times.

