def test_not_write_duplicate_yaml_keys(self):
        self.assertTrue(device_tracker.setup(self.hass, {}))

        device_tracker.see(self.hass, 'mac_1', host_name='hello')
        device_tracker.see(self.hass, 'mac_2', host_name='hello')

        self.hass.pool.block_till_done()

        config = device_tracker.load_config(self.yaml_devices, self.hass,
                                            timedelta(seconds=0), 0)
        assert len(config) == 2
dosm_comma_list : dosm_comma_list COMMA test
dataset/ETHPy150Open home-assistant/home-assistant/tests/components/device_tracker/test_init.py/TestComponentsDeviceTracker.test_not_write_duplicate_yaml_keys--crossover with--dataset/ETHPy150Open nucleic/enaml/enaml/core/parser.py/p_dosm_comma_list2