Addition overloading in Python behaviour x+y vs y+x

问题

In Python if I have

class Foo:
  def __add__(self, other):
    return 123

then I can do Foo()+1 and get 123.

But if I do 1+Foo() I get an exception because int doesn't know how to add Foos.

Is there a workaround so that 1+Foo() works too?

回答1:

Implement the __radd__() method as well.

来源：https://stackoverflow.com/questions/20832112/addition-overloading-in-python-behaviour-xy-vs-yx