def METHOD_NAME(self):
    self.dps[PRESET_DPS] = "normal"
    self.assertEqual(self.subject.preset_mode, "normal")
    self.dps[PRESET_DPS] = "nature"
    self.assertEqual(self.subject.preset_mode, "nature")
    self.dps[PRESET_DPS] = "sleep"
    self.assertEqual(self.subject.preset_mode, "sleep")
    self.dps[PRESET_DPS] = None
    self.assertIs(self.subject.preset_mode, None)