code: def POST(self, courseid):  # pylint: disable=arguments-differ
          
          course = self.get_course(courseid)
  
          user_input = web.input()
          if "unregister" in user_input and course.allow_unregister():
              self.user_manager.course_unregister_user(course, self.user_manager.session_username())
              raise web.seeother(self.app.get_homepath() + '/mycourses')
  
          return self.show_page(course)
docs: POST request