Why Methods Bind Automatically

class Foo:
    def bar(self):
        return "bar"

f = Foo()
print(f.bar)

This prints something like <bound method Foo.bar of <...>> rather than the plain function object stored in Foo.__dict__['bar']. What makes that happen?

f.bar triggers getattr, which Python auto-generates for every class to wrap functions into bound methods

Functions implement the descriptor protocol: they define get, so accessing bar through an instance invokes function.get(f, Foo), which returns a bound method wrapping f

Python hardcodes a special case for names that look like method calls, separate from normal attribute lookup

Foo.init copies every function from the class body into the instance's own dict, binding self at construction time