Fix PEP257 issues

homeassistant/exceptions.py

@@ -1,23 +1,28 @@
-""" Exceptions used by Home Assistant """
+"""Exceptions used by Home Assistant."""
 
 
 class HomeAssistantError(Exception):
-    """ General Home Assistant exception occured. """
+    """General Home Assistant exception occurred."""
+
     pass
 
 
 class InvalidEntityFormatError(HomeAssistantError):
-    """ When an invalid formatted entity is encountered. """
+    """When an invalid formatted entity is encountered."""
+
     pass
 
 
 class NoEntitySpecifiedError(HomeAssistantError):
-    """ When no entity is specified. """
+    """When no entity is specified."""
+
     pass
 
 
 class TemplateError(HomeAssistantError):
-    """ Error during template rendering. """
+    """Error during template rendering."""
+
     def __init__(self, exception):
+        """Initalize the error."""
         super().__init__('{}: {}'.format(exception.__class__.__name__,
                                          exception))