Question

I have a class called WeakBoundMethod (source on codereview.se). I’d like some guidelines about how I should implement __hash__(). Also, Python 3 automatically provides a __repr__() function, so I guess I shouldn’t bother redefining it then (?). What about __str__(), which I understand is a human readable text representation of the object; should I define that as well? any guidelines?

About the hashing function…
I’d like it to generate the hash based on the __self__ and __func__ of the bound method it is wrapping. How can I do that?

Answer 1

If in doubt, don’t implement magic methods. The defaults are there for a reason and will be fine. In your case, it’s completely unnecessary to implement __hash__ (and if you would implement it, you’d have to implement __eq__ as well) unless you expect someone to have a set or dictionary of methods.

__str__ can be useful. In your case, its result should include:

• The class name, to avoid confusion with anything else
• Whether the function is alive or not
• If it is alive, its str() result to identify the function, say, by name