1 #!/usr/bin/env python 2 3 a = 1 4 b = 2 5 6 class X: 7 def __contains__(self, other): 8 return 1 9 10 x = X() 11 12 result_3 = 0 13 result_4 = 4 14 15 if a is not x is not b: 16 result_3 = 3 17 18 if a is not x is b: 19 result_4 = 0 20 21 # vim: tabstop=4 expandtab shiftwidth=4