[RLlib] Allow SAC to use custom models as Q- or policy nets and deprecate "state-preprocessor" for image spaces. (#13522)

rllib/utils/threading.py

@@ -22,6 +22,6 @@ def with_lock(func: Callable):
         except AttributeError:
             raise AttributeError(
                 "Object {} must have a `self._lock` property (assigned to a "
-                "threading.Lock() object in its constructor)!".format(self))
+                "threading.RLock() object in its constructor)!".format(self))
 
     return wrapper