Python : Operator Overloading a specific type

I'd like to be able to ha开发者_运维技巧ve the operator of my class interact with regular types in a way that I define. Lets say, for example, I have:

class Mynum(object):
  def __init__(self, x):
   self.x = x
  def __add__(self, other):
   return self.x + other.x

a = Mynum(1)
b = Mynum(2)

print a+b

This works just fine, but now if I try to do:

print a+2

I get an error since an int does not have a member named x. How do I define Mynum + int in the class? This sounds like a job for decorators or metaclasses, but I'm terribly unfamiliar with their usage. This question seems similar, but not quite identical.

def __add__(self, other):
    if isinstance(other, self.__class__):
        return self.x + other.x
    elif isinstance(other, int):
        return self.x + other
    else:
        raise TypeError("unsupported operand type(s) for +: '{}' and '{}'").format(self.__class__, type(other))

class Mynum(object):
    def __init__(self, x):
        self.x = x
    def __add__(self, other):
        try:
            return self.x + other.x
        except AttributeError:
            return self.x + other
    __radd__=__add__

a = Mynum(1)
b = Mynum(2)

print(a+b)
# 3
print(a+2)
# 3
print(2+a)
# 3

Why use the extra switching and/or exception handling? Using the following would be a simpler approach:

class MyNum(object):
    def __init__(self, x):
        self.x = x
    def __add__(self, other):
        return other + self.x
    __radd__ = __add__
x = MyNum(5)
y = MyNum(6)
print x + 2
7
print 2 + x
7
print x + y
11
print y + x
11