原题需要区间求和,要求是用那个定义函数

我写了一串代码,但是运行不出来,请问哪里出错了呀?有没有人帮一下忙重新弄一下

关注望采纳!谢谢
def intervalSum(n, m):
sum = 0
for i in range(n ,m):
sum += i
return sum
print("Sum from 1 to 10 is {}".format(intervalSum(1,10)))
print("Sum from 20 to 37 is {}".format(intervalSum(20,37)))
print("Sum from 35 to 49 is {}".format(intervalSum(35,49)))
