1 def f(x): 2 def g(y, x=x): 3 while 1: 4 def h(z, x=x, y=y): 5 return x, y, z, a 6 a = 4 # not available for h, available in Python 7 return h 8 return g 9 10 result = f(1)(2)(3) 11 assert result == (1, 2, 3, 4)