#decorator function
def dec(func):
amount = 0
def wrapper(sales):
nonlocal amount
amount += sales
print("before external function is called")
func(sales)
print("after external function is called:", amount)
return wrapper
@dec
def production(sales):
print(sales)
@dec
def shipping(cost):
print("total expenses:", cost)
production(1)
production(2)
production(3)
shipping(10)
shipping(20)
shipping(30)