Can you monkey patch methods on core types in Pyth

Question

Ruby can add methods to the Number class and other core types to get effects like this:

1.should_equal(1)

But it seems like Python cannot do this. Is this true? And if so, why? Does it have something to do with the fact that type can't be modified?

Update: Rather than talking about different definitions of monkey patching, I would like to just focus on the example above. I have already concluded that it cannot be done as a few of you have answered. But I would like a more detailed explanation of why it cannot be done, and maybe what feature, if available in Python, would allow this.

To answer some of you: The reason I might want to do this is simply aesthetics/readability.

 item.price.should_equal(19.99)

This reads more like English and clearly indicates which is the tested value and which is the expected value, as supposed to:

should_equal(item.price, 19.99)

This concept is what Rspec and some other Ruby frameworks are based on.

Answer 1

Here's an example of implementing item.price.should_equal, although I'd use Decimal instead of float in a real program:

class Price(float):
    def __init__(self, val=None):
        float.__init__(self)
        if val is not None:
            self = val

    def should_equal(self, val):
        assert self == val, (self, val)

class Item(object):
    def __init__(self, name, price=None):
        self.name = name
        self.price = Price(price)

item = Item("spam", 3.99)
item.price.should_equal(3.99)

Answer 2

No, you can't do that in Python. I consider it to be a good thing.