I tried implementing insertion sort in python. I tried to follow the values on paper but once the counting variable i gets bigger than len(s) I don't know what to do, how/why does it still run?

def sort_numbers(s):
for i in range(1, len(s)):
val = s[i]
j = i - 1
while (j >= 0) and (s[j] > val):
s[j+1] = s[j]
j = j - 1
s[j+1] = val
def main():
x = eval(input("Enter numbers to be sorted: "))
x = list(x)
sort_numbers(x)
print(x)