def test_math_g02_unknowns(self):
     assert(mod.get_mean_length(self.unk_dict)    == 1)
 def test_math_g05_medium_sets(self):
     assert(mod.get_mean_length(self.med_dict_1)  == 1.5)
 def test_math_g01_emptiness(self):
     assert(mod.get_mean_length(self.empty_dict_1) is None)