Oops, `__kwdefaults__` is only for keyword-only arguments fn = lambda x, *args, y=3: 0 print(fn.__defaults__, fn.__kwdefaults__) # prints None {'y': 3

Oops, `__kwdefaults__` is only for keyword-only arguments fn = lambda x, *args, y=3: 0 print(fn.__defaults__, fn.__kwdefaults__) # prints None {'y': 3} Source: https://stackoverflow.com/questions/17533929/what-is-the-use-of-kwdefaults-which-is-a-function-object-attribute https://stackoverflow.com/questions/17533929/what-is-the-use...