FEM: Python object base classes, some tweaks

src/Mod/Fem/femguiobjects/ViewProviderFemConstraint.py

@@ -97,8 +97,7 @@ def doubleClicked(self, vobj):
             FreeCAD.Console.PrintError(message + "\n")
         return True
 
-    def __getstate__(self):
-        return None
-
+    # a few objects had this method in their class before the move to this base class
+    # these objects will give a setAttr failed error on document loading without this method
     def __setstate__(self, state):
         return None

src/Mod/Fem/femobjects/FemConstraint.py

@@ -37,4 +37,10 @@ def __init__(self, obj):
         self.Object = obj  # keep a ref to the DocObj for nonGui usage
         obj.Proxy = self  # link between App::DocumentObject to this object
 
+    # a few objects had this method in their class before the move to this base class
+    # these objects will give a setAttr failed error on document loading without this method
+    def __setstate__(self, state):
+        if state:
+            self.Type = state
+
 ##  @}