In order to represent a chessboard in a program, write a chessboard function that will return an array of arrays containing the squares coordinates.
[
['a - 1', 'a - 2', 'a - 3', 'a - 4', 'a - 5', 'a - 6', 'a - 7', 'a - 8'],
['b - 1', 'b - 2', 'b - 3', 'b - 4', 'b - 5', 'b - 6', 'b - 7', 'b - 8'],
...,
['h - 1', 'h - 2', 'h - 3', 'h - 4', 'h - 5', 'h - 6', 'h - 7', 'h - 8'],
]