text: from rest_framework import serializers
  from task.models import Group, Task, Step
  
  class GroupSerializer(serializers.HyperlinkedModelSerializer):
      user = serializers.ReadOnlyField(source='user.username')
      node_id = serializers.ReadOnlyField(source='node.id')
      app = serializers.ReadOnlyField()
      class Meta:
          model = Group
          fields = ['url', 'id', 'node', 'node_id', 'user', 'app', 'name', 'sort', 'is_open', 'is_leaf', 'level', 'qty']
  
  class TaskSerializer(serializers.HyperlinkedModelSerializer):
      user = serializers.ReadOnlyField(source='user.username')
      class Meta:
          model = Task
          fields = ['url', 'user', 'name', 'created', 'in_my_day', 'important', 'completed', 'completion', 
                    'start', 'stop', 'remind', 'last_remind', 'repeat', 'repeat_num', 'repeat_days', 'categories',
                    'app_task', 'app_note', 'app_news', 'app_store', 'app_doc', 'app_warr', 'app_expen', 
                    'app_trip', 'app_fuel', 'app_apart', 'app_health', 'app_work', 'app_photo']
  
  class StepSerializer(serializers.HyperlinkedModelSerializer):
      user = serializers.ReadOnlyField(source='user.username')
      class Meta:
          model = Step
          fields = ['url', 'id', 'user', 'task', 'name', 'sort', 'completed']
  
  