报错

1.报错：TypeError: unsupported operand type(s) for +=: 'builtin_function_or_method' and 'int'

#-*- coding : utf-8 -*-
i = 0
sum = 0
while i <= 100:
        sum += i
        i += 1
print(sum)
i = 0
sum = 0
while i <= 100:
        sum += i
        i += 1
print(sum)

解释：python变量第一次出现只能出现在赋值左侧，不能出现在右侧。否则无法解析。