Foobar problem on staircase

partitions.py

def print_util(mat):
    for i in mat:
        for j in i:
            print(j, end=" ")
        print()
def solution(number):
    mat = [[0 for i in range(number+1)] for i in range(number+1)]
    mat[0][0] = 1
    # The first row is skipped
    for summands in range(1,number+1):
        for sums in range(number+1):
            mat[summands][sums] = mat[summands-1][sums]
            if sums >= summands:
                mat[summands][sums] += mat[summands-1][sums - summands]
    return mat[-1][-1] -1
    print_util(mat)