has_callback method for option

tiramisu/option.py

@@ -149,6 +149,12 @@ class Option(HiddenBaseType, DisabledBaseType, ModeBaseType):
     def getcallback(self):
         return self.callback
     
+    def has_callback(self):
+        if self.callback == None:
+            return False
+        else:
+            return True
+
     def getcallback_params(self):
         return self.callback_params