Block the Square in Tic Tac Toe

Create a function that returns a number which can block the player from reaching 3 in a row in a game of Tic Tac Toe. The number given as an argument will correspond to a grid of Tic Tac Toe: topleft is 0, topright is 2, bottomleft is 6, and bottomright is 8.

• Create a function that takes two numbers a, b and returns another number.
• This number should be the final one in a line to block the player from winning.

Examples

block_player(0, 3) ➞ 6

block_player(0, 4) ➞ 8

block_player(3, 5) ➞ 4

Notes

The values given will always have two filled squares in a line.