my solution below works on my idee yet i get "none object is not iterable" error here, I want to keep going i like this website so pls fix this sheet.

def split_pairs(a):

for letter in a:
    if len(a) % 2 == 0:
        print(a[:(len(a)) // 2] + "," + a[(len(a)) // 2:])
    else:
        print(a[:(len(a)) // 2 + 1] + "," + a[(len(a)) // 2 + 1:] + "_")