def testFilter (self):
self.assertEquals (Nil, Nil.filter (lambda x: True))
self.assertEquals (List (2, 4), List (1, 2, 3, 4, 5).filter (_ % 2 == 0))
self.assertEquals (Nil, List (1, 2, 3, 4, 5).filter (_ > 10))
self.assertEquals (List, List (1, 2, 3, 4, 5).filter (lambda x: x > 10).__class__)
pass
