ES6 got this right too.
This design decision makes me die a little every time I have to do:
def foo(x=None):
if not x:
x = []
...This design decision makes me die a little every time I have to do:
def foo(x=None):
if not x:
x = []
... if x is None:
x = []
x = [] if x is None else xx = x or []