Exercise 1: Grid Sum

Your Task

Write a function grid_sum(grid) that takes a 2D list of integers and returns the sum of all numbers in the grid.

Examples

grid1 = [
    [1, 2, 3],
    [4, 5, 6]
]
print(grid_sum(grid1))  # 21

grid2 = [
    [10, -5],
    [3,   7],
    [2,  -1]
]
print(grid_sum(grid2))  # 16

Hints