TypeError: 'int' object is not iterable какая проблема?

def sequence_sum(begin_number, end_number, step):
result = 0
for i in end_number:
begin_number += step
result += begin_number
if (begin_number == end_number):
break
return result
if (begin_number > end_number):
return 0

Код

def sequence_sum(begin_number, end_number, step):

    result = 0

    for i in end_number:

        begin_number += step

        result += begin_number

        if (begin_number == end_number):

            break

            return result

    if (begin_number > end_number):

        return 0

при запуске такая ошибка:
for i in end_number: TypeError: 'int' object is not iterable

Возможно элементарно, но я начал буквально пару дней назад, заранее спасибо!