L2SS-412: Fixed typo, explained explicitly that ping() can and should throw in case of issues

devices/clients/comms_client.py

@@ -13,10 +13,13 @@ class AbstractCommClient(ABC):
 
     @abstractmethod
     def stop(self):
-        """ Start communication with the client. """
+        """ Stop communication with the client. """
 
     def ping(self):
-        """ Check whether the connection is still alive. Raises an exception if not. """
+        """ Check whether the connection is still alive.
+        
+            Clients that override this method must raise an Exception if the
+            connection died. """
         pass
 
     @abstractmethod
@@ -125,7 +128,11 @@ class CommClient(AbstractCommClient, Thread):
                 time.sleep(self.try_interval)
 
     def ping(self):
-        return
+        """ Check whether the connection is still alive.
+        
+            Clients that override this method must raise an Exception if the
+            connection died. """
+        pass
 
     def stop(self):
         """