Assertion error on third example

length = len(data)
integrity = 1

if length >= 10:
    for char in data:
        if char.isdigit():
            integrity += 1
        if char.islower():
            integrity += 1
        if char.isupper():
            integrity += 1
        if char.isspace():
            integrity += 1


if integrity >= 5:
    return True
else:
    return False

I would be grateful if someone would explain to me, why this code gets an assertion error on the third example "3rd example"