frappy_psi.manual_valves: make persistent and clean up

Change-Id: Ifbdc886f556064745a7aaffbfdc1bad2ad74632e

frappy_psi/manual_valves.py

@@ -19,20 +19,14 @@
 #
 # *****************************************************************************
 
-from frappy.core import Readable, Parameter, FloatRange, BoolType, StringIO, HasIO, \
-    Property, StringType, Writable, IntRange, IDLE, BUSY, ERROR
-from frappy.errors import CommunicationFailedError
+from frappy.core import Parameter, BoolType, Writable
+from frappy.persistent import PersistentMixin, PersistentParam
 
-class ManualValve(Writable):
-    target = Parameter('Valve target', datatype = BoolType())
+
+class ManualValve(PersistentMixin, Writable):
+    target = PersistentParam('Valve target', datatype=BoolType(), persistent='auto')
     value = Parameter('Valve state', datatype=BoolType())
     
-    def read_value(self):
-        return self.value
-    
     def write_target(self, target):
         self.value = target
         return self.value
-    
-    def read_status(self):
-        return IDLE, ''