text: from django.contrib.auth import REDIRECT_FIELD_NAME
  from django.contrib.auth.decorators import user_passes_test
  
  
  def viewer_required(function=None, redirect_field_name=REDIRECT_FIELD_NAME, login_url='login'):
      '''
      Decorator for views that checks that the logged in user is a student,
      redirects to the log-in page if necessary.
      '''
      actual_decorator = user_passes_test(
          lambda u: u.is_active and u.is_viewer,
          login_url=login_url,
          redirect_field_name=redirect_field_name
      )
      if function:
          return actual_decorator(function)
      return actual_decorator
  
  
  def editor_required(function=None, redirect_field_name=REDIRECT_FIELD_NAME, login_url='login'):
      '''
      Decorator for views that checks that the logged in user is a teacher,
      redirects to the log-in page if necessary.
      '''
      actual_decorator = user_passes_test(
          lambda u: u.is_active and u.is_editor,
          login_url=login_url,
          redirect_field_name=redirect_field_name
      )
      if function:
          return actual_decorator(function)
      return actual_decorator
  