code: def to_representation(self, instance):
          
          updated_course_run = copy.deepcopy(instance)
          enterprise_customer_catalog = self.context['enterprise_customer_catalog']
          updated_course_run['enrollment_url'] = enterprise_customer_catalog.get_course_run_enrollment_url(
              updated_course_run['key']
          )
          return updated_course_run
docs: Return the updated course run data dictionary.
  
          Arguments:
              instance (dict): The course run data.
  
          Returns:
              dict: The updated course run data.