# Buggy code
def __init__(self, device, device_type, xiaomi_hub):
    """Initialize the Xiaomi device."""
    self._state = None
    self._is_available = True
    self._sid = device["sid"]
    self._name = "{}_{}".format(device_type, self._sid)
    self._type = device_type
    self._write_to_hub = xiaomi_hub.write_to_hub
    self._get_from_hub = xiaomi_hub.get_from_hub
    self._device_state_attributes = {}
    self._remove_unavailability_tracker = None
    self._xiaomi_hub = xiaomi_hub
    self.parse_data(device["data"], device["raw_data"])
    self.parse_voltage(device["data"])

    if hasattr(self, "_data_key") and self._data_key:  # pylint: disable=no-member
        self._unique_id = slugify(
            "{}-{}".format(
                self._data_key,  # pylint: disable=no-member
                self._sid,
            )
        )
    else:
        self._unique_id = slugify("{}-{}".format(self._type, self._sid))


# Traceback (miio.device.DeviceException)
2018-03-29 03:47:13 ERROR (Thread-7) [miio.device] Unable to discover a device at address 192.168.10.213
2018-03-29 03:47:13 ERROR (MainThread) [homeassistant.components.fan] Error while setting up platform smart_mi_fan
Traceback (most recent call last):
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/entity_platform.py", line 82, in async_setup
SLOW_SETUP_MAX_WAIT, loop=hass.loop)
File "/usr/lib/python3.5/asyncio/tasks.py", line 400, in wait_for
return fut.result()
File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
raise self._exception
File "/usr/lib/python3.5/concurrent/futures/thread.py", line 55, in run
result = self.fn(*self.args, **self.kwargs)
File "/home/homeassistant/.homeassistant/custom_components/fan/smart_mi_fan.py", line 77, in setup_platform
SmartMiFan(hass, name, host, token),
File "/home/homeassistant/.homeassistant/custom_components/fan/smart_mi_fan.py", line 165, in __init__
self._state_attrs = self.fan_get_prop()
File "/home/homeassistant/.homeassistant/custom_components/fan/smart_mi_fan.py", line 404, in fan_get_prop
"natural_level", "child_lock", "buzzer", "led_b"])
File "/srv/homeassistant/lib/python3.5/site-packages/miio/device.py", line 210, in send
self.do_discover()
File "/srv/homeassistant/lib/python3.5/site-packages/miio/device.py", line 148, in do_discover
raise DeviceException("Unable to discover the device %s" % self.ip)
miio.device.DeviceException: Unable to discover the device 192.168.10.213

# Fixed code
def __init__(self, device, device_type, xiaomi_hub):
    """Initialize the Xiaomi device."""
    self._state = None
    self._is_available = True
    self._sid = device["sid"]
    self._name = "{}_{}".format(device_type, self._sid)
    self._type = device_type
    self._write_to_hub = xiaomi_hub.write_to_hub
    self._get_from_hub = xiaomi_hub.get_from_hub
    self._device_state_attributes = {}
    self._remove_unavailability_tracker = None
    self._xiaomi_hub = xiaomi_hub
    self.parse_data(device["data"], device["raw_data"])
    self.parse_voltage(device["data"])

    if hasattr(self, "_data_key") and self._data_key:  # pylint: disable=no-member
        self._unique_id = "{}{}".format(
            self._data_key,  # pylint: disable=no-member
            self._sid,
        )
    else:
        self._unique_id = "{}{}".format(self._type, self._sid)