If the string contains an odd number of characters, how to add a ( _ ) character after the last character

How to add a character(_) after the last character?

def split_string(string: str) -> list:
    n = 2
    list1 = [string[i: i + n] for i in range(0, len(string), n)]
    return list1


print(split_string("123456"))  # ["12", "34", "56"]
print(split_string("ab cd ef"))  # ["ab", " c", "d ", "ef"]
print(split_string("abc"))  # ["ab", "c_"]
print(split_string(" "))  # [" _"]
print(split_string(""))  # []

>Solution :

Just add a character to a temporary copy, and work with that:

def split_string(string: str) -> list:
    s = string + "_"   # <----
    list1 = [s[i: i + 2] for i in range(0, len(string), 2)]
    #        ^
    return list1