Python 2.7 简单Python转换器错误

我正在努力学习函数，想做一个简单的千克到磅，或者反之亦然。每当我运行代码时，它都会输出“无”，我不明白为什么

def convert(amount, measurement):
    if measurement == "kilograms":
        float(amount) * 2.2
    if measurement == "pounds":
        float(amount) / 2.2

amount_measure = raw_input("How many are you converting?")
amount_measurement = raw_input("What are you converting?")

if amount_measurement == 'kilograms':
    print "You have %r pounds." % convert(amount_measure, amount_measurement)

if amount_measurement == 'pounds':
    print "You have %r kilograms." % convert(amount_measure, amount_measurement)

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您需要返回这些值。使用return命令。像这样的

return float(amount) * 2.2

---

非常感谢你！

def convert(amount, measurement):
    if measurement == "kilograms":
        return float(amount) * 2.2
    if measurement == "pounds":
        return float(amount) / 2.2

amount_measure = raw_input("How many are you converting?")
amount_measurement = raw_input("What are you converting?")

if amount_measurement == 'kilograms':
    print "You have %r pounds." % convert(amount_measure, amount_measurement)

if amount_measurement == 'pounds':
    print "You have %r kilograms." % convert(amount_measure, amount_measurement)