def test_calc_2 (self) :
     cycle_length = _calc_cycle_length(20)
     self.assertTrue(cycle_length == 8)
 def test_calc_3 (self) :
     cycle_length = _calc_cycle_length(1)
     self.assertTrue(cycle_length == 1)
 def test_calc_1 (self) :
     cycle_length = _calc_cycle_length(5)
     self.assertTrue(cycle_length == 6)