Помогите найти ошибку в коде, пожалуйста

def harmfully(*data, letters=str):
let = letters.split()
let_big = letters.upper().split()
for iterait in data:
if (let not in iterait or let_big not in iterait and len(iterait) % len(letters) == 0 and
iterait[0].upper() +iterait[1:].lower() != iterait):
data.remove(iterait)

data = ["And in the evenings", "people sat on their porch", "talking to each other if they wanted to"]
print(*harmfully(*data, letters='Ap'), sep='\n')