python中function调用另一个function

背景：当一个函数可以被解耦合出来时，可以将一个大功能的函数分解成不同的函数。
参考代码实例：

def computeNumber(a,b):
    c = a + b
    d = a * b
    e = c - d
    return c,d,e

print computeNumber(2,3)

c1, d1, e1 = computeNumber(2,3)
print c1, d1, e1

[output]:
(5, 6, -1)
5 6 -1

def computerNumber(a,b,c,d):
    sum_number1 = a + b + c + d
    # 对另一函数值得调用
    c1, d1, e1 = computeNumber(a,b)
    sum_number2 = c1 + d1 + e1
    sum_number_total = sum_number1 + sum_number2
    print "sum_number1:",sum_number1
    print "sum_number2:",sum_number2
    print "sum_number_total:",sum_number_total

computerNumber(2,3,4,5)
[output]:
sum_number1: 14
sum_number2: 10
sum_number_total: 24