Conditionally show calculator

common/lib/xmodule/xmodule/course_module.py

@@ -127,6 +127,24 @@ class CourseDescriptor(SequenceDescriptor):
     def grade_cutoffs(self):
         return self._grading_policy['GRADE_CUTOFFS']
 
+    @property
+    def show_calculator(self):
+        return self.metadata.get("show_calculator", None) == "Yes"
+
+    @lazyproperty
+    def __grading_policy(self):
+        policy_string = ""
+
+        try:
+            with self.system.resources_fs.open("grading_policy.json") as grading_policy_file:
+                policy_string = grading_policy_file.read()
+        except (IOError, ResourceNotFoundError):
+            log.warning("Unable to load course settings file from grading_policy.json in course " + self.id)
+
+        grading_policy = load_grading_policy(policy_string)
+
+        return grading_policy
+
     @lazyproperty
     def grading_context(self):
         """