Fix PEPE257 issues

homeassistant/components/sensor/mqtt.py

@@ -21,8 +21,7 @@ DEPENDENCIES = ['mqtt']
 
 # pylint: disable=unused-argument
 def setup_platform(hass, config, add_devices_callback, discovery_info=None):
-    """Add MQTT Sensor."""
-
+    """Setup MQTT Sensor."""
     if config.get('state_topic') is None:
         _LOGGER.error("Missing required variable: state_topic")
         return False
@@ -38,9 +37,11 @@ def setup_platform(hass, config, add_devices_callback, discovery_info=None):
 
 # pylint: disable=too-many-arguments, too-many-instance-attributes
 class MqttSensor(Entity):
-    """Represents a sensor that can be updated using MQTT."""
+    """Representation of a sensor that can be updated using MQTT."""
+
     def __init__(self, hass, name, state_topic, qos, unit_of_measurement,
                  value_template):
+        """Initialize the sensor."""
         self._state = STATE_UNKNOWN
         self._hass = hass
         self._name = name
@@ -65,15 +66,15 @@ class MqttSensor(Entity):
 
     @property
     def name(self):
-        """The name of the sensor."""
+        """Return the name of the sensor."""
         return self._name
 
     @property
     def unit_of_measurement(self):
-        """Unit this state is expressed in."""
+        """Return the unit this state is expressed in."""
         return self._unit_of_measurement
 
     @property
     def state(self):
-        """Returns the state of the entity."""
+        """Return the state of the entity."""
         return self._state