所有方法的第一个参数通常称为 self.它指的是为其调用方法的实例.

The first argument of all methods is usually called self. It refers to the instance for which the method is being called.

假设您有:

class A(object):
    def foo(self):
        print 'Foo'

    def bar(self, an_argument):
        print 'Bar', an_argument

然后，做:

a = A()
a.foo() #prints 'Foo'
a.bar('Arg!') #prints 'Bar Arg!'

这个被称为 self 并没有什么特别之处，你可以执行以下操作:

---

There's nothing special about this being called self, you could do the following:

class B(object):
    def foo(self):
        print 'Foo'

    def bar(this_object):
        this_object.foo()

然后，做:

b = B()
b.bar() # prints 'Foo'

在您的具体情况下:

---

In your specific case:

dangerous_device = MissileDevice(some_battery)
dangerous_device.move(dangerous_device.RIGHT) 

(正如评论中所建议的，MissileDevice.RIGHT 在这里可能更合适！)

(As suggested in comments MissileDevice.RIGHT could be more appropriate here!)

您可以在模块级别声明所有常量，因此您可以这样做:

You could declare all your constants at module level though, so you could do:

dangerous_device.move(RIGHT)

然而，这将取决于您希望如何组织代码！

This, however, is going to depend on how you want your code to be organized!