我無法讓我的函數返回全局變量

Question

回溯（最近一次調用最后一次）：文件“C：\\ Users \\ Mitch \\ Documents \\ lab3.py”，第18行，在main（）文件“C：\\ Users \\ Mitch \\ Documents \\ lab3.py”中，第15行，在主要finddiscount（數量）文件“C：\\ Users \\ Mitch \\ Documents \\ lab3.py”，第2行，在finddiscount中，如果數量> = 1且數量<= 9：NameError：全局名稱'數量'未定義

def finddiscount(discount):
    if quantity >= 1 and quantity <= 9:
        discount = "0%"
    elif quantity >= 10 and quantity <= 19:
        discount = "20%"
    elif quantity >= 20 and quantity <= 49:
        discount = "30%"
    elif quantity >= 50 and quantity <= 99:
        discount = "40%"
    elif quantity >= 100:
        discount = "50%"
    print (discount)    
def main():
    quantity = int(input("How many packages where purchased?"))
    finddiscount(quantity)
    price = float(input("How much is each item?"))
    return
main()

Answer 1

嘗試

def finddiscount(quantity):   # not discount!