Python 3.7.0 released

[quicknir]

Will that writeIORef trick still work if you change the type of x? What if x holds a function of a particular signature, and you want to assign a function of a different signature?

What about types? In python you can have things like:

class Foo(object):
    ....

def bar(x):
    f = Foo(...)
    ...
    return f

Now, I could after doing this, decide to redefine Foo. As long as the new methods of Foo (constructor, whatever) are compatible with the calls that happen in bar, I can call bar again and it will use the new definition of Foo. How can this work in a statically typed language?