old_contents: # -*- coding: utf-8 -*-
  
  from rest_framework import serializers
  
  from taiga.base.serializers import PickleField, NeighborsSerializerMixin
  
  from . import models
  
  
  class IssueSerializer(serializers.ModelSerializer):
      tags = PickleField(required=False)
      comment = serializers.SerializerMethodField("get_comment")
      is_closed = serializers.Field(source="is_closed")
  
      class Meta:
          model = models.Issue
  
      def get_comment(self, obj):
          return ""
  
  
  class IssueNeighborsSerializer(NeighborsSerializerMixin, IssueSerializer):
  
      def serialize_neighbor(self, neighbor):
          return NeighborIssueSerializer(neighbor).data
  
  
  class NeighborIssueSerializer(serializers.ModelSerializer):
      class Meta:
          model = models.Issue
          fields = ("id", "ref", "subject")
          depth = 0
  
new_contents: # -*- coding: utf-8 -*-
  
  from rest_framework import serializers
  
  from taiga.base.serializers import PickleField, NeighborsSerializerMixin
  
  from . import models
  
  
  class IssueSerializer(serializers.ModelSerializer):
      tags = PickleField(required=False)
      is_closed = serializers.Field(source="is_closed")
  
      class Meta:
          model = models.Issue
  
  
  class IssueNeighborsSerializer(NeighborsSerializerMixin, IssueSerializer):
  
      def serialize_neighbor(self, neighbor):
          return NeighborIssueSerializer(neighbor).data
  
  
  class NeighborIssueSerializer(serializers.ModelSerializer):
      class Meta:
          model = models.Issue
          fields = ("id", "ref", "subject")
          depth = 0
  
subject: Remove unnecessary field from IssueSerializer