old_contents: __author__ = 'irwan'
  
  from rest_framework import serializers
  from feti.models.course import Course
  
  
  class CourseSerializer(serializers.ModelSerializer):
      class Meta:
          model = Course
  
new_contents: from rest_framework import serializers
  from feti.models.course import Course
  
  __author__ = 'irwan'
  
  
  class CourseSerializer(serializers.ModelSerializer):
      class Meta:
          model = Course
  
subject: Fix flake8 error