old_contents: from django.contrib import admin
  from modeltranslation.admin import TranslationAdmin
  from django import forms
  from dal import autocomplete
  
  from . import models, translation
  
  
  class TopicCollectionForm(forms.ModelForm):
      class Meta:
          model = models.TopicCollection
          fields = ('__all__')
          widgets = {
              'sources': autocomplete.ModelSelect2Multiple(url='source:source_public_autocomplete')
          }
          
  @admin.register(models.TopicCollection)
  class TopicCollectionAdmin(TranslationAdmin):
      form = TopicCollectionForm
      prepopulated_fields = {"slug": ("title_cs",)}
  
new_contents: from django.contrib import admin
  from modeltranslation.admin import TranslationAdmin
  from django import forms
  from dal import autocomplete
  
  from . import models, translation
  
  
  class TopicCollectionForm(forms.ModelForm):
      class Meta:
          model = models.TopicCollection
          fields = ('__all__')
          widgets = {
              'sources': autocomplete.ModelSelect2Multiple(url='source:source_public_autocomplete')
          }
          
  @admin.register(models.TopicCollection)
  class TopicCollectionAdmin(TranslationAdmin):
      form = TopicCollectionForm
      # prepopulated_fields = {"slug": ("title_cs",)}
  
subject: fix topic colllection admin