Throw exception if function is called in the wrong state, instead of silent failure

RCUSCC/RCUSCC/wrappers.py

-from tango import DevState
+from tango import DevState, Except
 from functools import wraps
 import traceback
 
@@ -7,8 +7,7 @@ __all__ = ["only_in_states", "only_when_on", "fault_on_error"]
 def only_in_states(allowed_states):
     """
       Wrapper to call and return the wrapped function if the device is
-      in one of the given states. Otherwise None is returned and nothing
-      will be called.
+      in one of the given states. Otherwise a PyTango exception is thrown.
     """
     def wrapper(func):
         @wraps(func)
@@ -16,7 +15,8 @@ def only_in_states(allowed_states):
             if self.get_state() in allowed_states:
                 return func(self, *args, **kwargs)
 
-            return None
+            self.warn_stream("Illegal command: Function %s can only be called in states %s. Current state: %s" % (func.__name__, allowed_states, self.get_state()))
+            Except.throw_exception("IllegalCommand", "Function can only be called in states %s. Current state: %s" % (allowed_states, self.get_state()), func.__name__)
 
         return state_check_wrapper