'Updates the course\'s grading policy.'

def _update_grading_policy(self, passing=0.5):

    self.grading_policy = {'GRADER': [{'type': 'Homework', 'min_count': 1, 'drop_count': 0, 'short_label': 'HW', 'weight': 1.0}], 'GRADE_CUTOFFS': {'Pass': passing}}
    self.course.set_grading_policy(self.grading_policy)
    self.store.update_item(self.course, 0)
