use a simple Field attribute for weight now that type is enforced

mentoring/mentoring.py

@@ -68,17 +68,10 @@ class MentoringBlock(XBlockWithLightChildren):
                                  default=False, scope=Scope.content)
     display_submit = Boolean(help="Allow to submit current block?", default=True, scope=Scope.content)
     xml_content = String(help="XML content", default='', scope=Scope.content)
-    max_grade = Float(help="Defines the maximum total grade of the block.", default=0, scope=Scope.content)
+    weight = Float(help="Defines the maximum total grade of the block.", default=0, scope=Scope.content)
     icon_class = 'problem'
     has_score = True
 
-    @property
-    def weight(self):
-        return float(self.max_grade)
-    @weight.setter
-    def weight(self, value):
-        self.max_grade = value
-
     def student_view(self, context):
         fragment, named_children = self.get_children_fragment(context, view_name='mentoring_view',
                                                               not_instance_of=MentoringMessageBlock)