old_contents: """
  Signal handler for enabling/disabling self-generated certificates based on the course-pacing.
  """
  from celery.task import task
  from django.dispatch import receiver
  
  from certificates.models import CertificateGenerationCourseSetting
  from openedx.core.djangoapps.models.course_details import COURSE_PACING_CHANGE
  
  
  @receiver(COURSE_PACING_CHANGE, dispatch_uid="course_pacing_changed")
  def _listen_for_course_publish(sender, course_key, course_self_paced, **kwargs):  # pylint: disable=unused-argument
      """
      Catches the signal that course pacing has changed and enable/disable
      the self-generated certificates according to course-pacing.
      """
      enable_self_generated_certs.delay(course_key, course_self_paced)
  
  
  @task()
  def enable_self_generated_certs(course_key, course_self_paced):
      """
      Enable or disable self-generated certificates for a course according to pacing.
      """
      CertificateGenerationCourseSetting.set_enabled_for_course(course_key, course_self_paced)
new_contents: """
  Signal handler for enabling/disabling self-generated certificates based on the course-pacing.
  """
  from celery.task import task
  from django.dispatch import receiver
  from opaque_keys.edx.keys import CourseKey
  
  from certificates.models import CertificateGenerationCourseSetting
  from openedx.core.djangoapps.models.course_details import COURSE_PACING_CHANGE
  
  
  @receiver(COURSE_PACING_CHANGE, dispatch_uid="course_pacing_changed")
  def _listen_for_course_publish(sender, course_key, course_self_paced, **kwargs):  # pylint: disable=unused-argument
      """
      Catches the signal that course pacing has changed and enable/disable
      the self-generated certificates according to course-pacing.
      """
      enable_self_generated_certs.delay(unicode(course_key), course_self_paced)
  
  
  @task()
  def enable_self_generated_certs(course_key, course_self_paced):
      """
      Enable or disable self-generated certificates for a course according to pacing.
      """
      course_key = CourseKey.from_string(course_key)
      CertificateGenerationCourseSetting.set_enabled_for_course(course_key, course_self_paced)
  
subject: fix coursekey error