Update/add docstrings (PEP257)

homeassistant/components/sensor/demo.py

@@ -1,6 +1,4 @@
 """
-homeassistant.components.sensor.demo
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Demo platform that has a couple of fake sensors.
 """
 from homeassistant.const import ATTR_BATTERY_LEVEL, TEMP_CELCIUS
@@ -9,7 +7,7 @@ from homeassistant.helpers.entity import Entity
 
 # pylint: disable=unused-argument
 def setup_platform(hass, config, add_devices, discovery_info=None):
-    """ Sets up the Demo sensors. """
+    """Sets up the Demo sensors."""
     add_devices([
         DemoSensor('Outside Temperature', 15.6, TEMP_CELCIUS, 12),
         DemoSensor('Outside Humidity', 54, '%', None),
@@ -17,8 +15,7 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
 
 
 class DemoSensor(Entity):
-    """ A Demo sensor. """
-
+    """A Demo sensor."""
     def __init__(self, name, state, unit_of_measurement, battery):
         self._name = name
         self._state = state
@@ -27,27 +24,27 @@ class DemoSensor(Entity):
 
     @property
     def should_poll(self):
-        """ No polling needed for a demo sensor. """
+        """No polling needed for a demo sensor."""
         return False
 
     @property
     def name(self):
-        """ Returns the name of the device. """
+        """Returns the name of the sensor."""
         return self._name
 
     @property
     def state(self):
-        """ Returns the state of the device. """
+        """Returns the state of the sensor."""
         return self._state
 
     @property
     def unit_of_measurement(self):
-        """ Unit this state is expressed in. """
+        """Unit this state is expressed in."""
         return self._unit_of_measurement
 
     @property
     def device_state_attributes(self):
-        """ Returns the state attributes. """
+        """Returns the state attributes."""
         if self._battery:
             return {
                 ATTR_BATTERY_LEVEL: self._battery,