code: def courses(self, request, pk=None):  # pylint: disable=invalid-name,unused-argument
          
          enterprise_customer = self.get_object()
          self.check_object_permissions(request, enterprise_customer)
          self.ensure_data_exists(
              request,
              enterprise_customer.catalog,
              error_message="No catalog is associated with Enterprise {enterprise_name} from endpoint '{path}'.".format(
                  enterprise_name=enterprise_customer.name,
                  path=request.get_full_path()
              )
          )
  
          # We have handled potential error cases and are now ready to call out to the Catalog API.
          catalog_api = CourseCatalogApiClient(request.user, enterprise_customer.site)
          courses = catalog_api.get_paginated_catalog_courses(enterprise_customer.catalog, request.GET)
  
          # An empty response means that there was a problem fetching data from Catalog API, since
          # a Catalog with no courses has a non empty response indicating that there are no courses.
          self.ensure_data_exists(
              request,
              courses,
              error_message=(
                  "Unable to fetch API response for catalog courses for "
                  "Enterprise {enterprise_name} from endpoint '{path}'.".format(
                      enterprise_name=enterprise_customer.name,
                      path=request.get_full_path()
                  )
              )
          )
  
          serializer = serializers.EnterpriseCatalogCoursesReadOnlySerializer(courses)
  
          # Add enterprise related context for the courses.
          serializer.update_enterprise_courses(enterprise_customer, catalog_id=enterprise_customer.catalog)
          return get_paginated_response(serializer.data, request)
docs: Retrieve the list of courses contained within the catalog linked to this enterprise.
  
          Only courses with active course runs are returned. A course run is considered active if it is currently
          open for enrollment, or will open in the future.