Refactor code to remove alerts as per lgtm and #1176.

evennia/contrib/tutorial_world/objects.py

@@ -826,13 +826,14 @@ class CmdAttack(Command):
             # call enemy hook
             if hasattr(target, "at_hit"):
                 # should return True if target is defeated, False otherwise.
-                return target.at_hit(self.obj, self.caller, damage)
+                target.at_hit(self.obj, self.caller, damage)
+                return
             elif target.db.health:
                 target.db.health -= damage
             else:
                 # sorry, impossible to fight this enemy ...
                 self.caller.msg("The enemy seems unaffacted.")
-                return False
+                return
         else:
             self.caller.msg(string + "{rYou miss.{n")
             target.msg(tstring + "{gThey miss you.{n")