语法“exp1<<variable<<exp2”在Python中是如何工作的？[closed]

当我在看书的时候，我发现了这个例子。

def apply_discount(product, discount):
    price = int(product['price'] * (1.0 - discount))
    assert 0 <= price <= product['price']
    return price

我从没见过语法0 <= price <= product['price']之前，很明显，这是在测试价格，应该>= 0和<= product['price'].我测试了这个功能，它按预期工作。我想对语法做更多的测试0 <= price <= product['price'].

a = 7
if 0 << a << 10:
    print('a is greater than or equal to 0 and less than or equal to 10')
else:
    print('a is not greater than or equal to 0 and less than or equal to 10')

它总是打印出来a is not greater than or equal to 0 and less than or equal to 10.为什么会这样？到底是什么0 << a << 10工作