old_contents: from django.contrib import admin
  from django_admin_bootstrapped.admin.models import SortableInline
  from .models import TestMe, TestThat, TestMeProxyForFieldsets, TestSortable
  
  
  class TestThatStackedInline(admin.StackedInline):
      model = TestThat
  
  
  class TestThatTabularInline(admin.TabularInline):
      model = TestThat
  
  
  class TestSortable(admin.StackedInline, SortableInline):
      model = TestSortable
      extra = 0
  
  
  class TestMeAdmin(admin.ModelAdmin):
      list_display = ['test_ip', 'test_url', 'test_int', 'test_img', 'test_file', 'test_date', 'test_char', 'test_bool', 'test_time', 'test_slug', 'test_text', 'test_email', 'test_float', 'test_bigint', 'test_positive_integer', 'test_decimal', 'test_comma_separated_int', 'test_small_int', 'test_nullbool', 'test_filepath', 'test_positive_small_int', ]
      search_fields = ['test_int', ]
      list_editable = ['test_int', ]
      list_filter = ['test_ip', 'test_url', 'test_int', ]
      list_per_page = 3
      date_hierarchy = 'test_date'
      inlines = [TestThatStackedInline, TestThatTabularInline, TestSortable]
      save_as = True
      save_on_top = True
  
  
  class TestMeAdminFieldsets(TestMeAdmin):
      actions_on_bottom = True
      fieldsets = (
          ('A fieldset', {
              'fields': ['test_m2m', 'test_ip', 'test_url', 'test_int', 'test_img', 'test_file', 'test_date', 'test_char', 'test_bool', 'test_time', 'test_slug', 'test_text', ],
          }),
          ('Another fieldset', {
              'fields': [('test_email', 'test_float'), 'test_bigint', ('test_positive_integer', 'test_decimal'), ('test_comma_separated_int', 'test_small_int'), ('test_nullbool', 'test_filepath'), 'test_positive_small_int', ],
          }),
      )
  
  admin.site.register(TestMeProxyForFieldsets, TestMeAdminFieldsets)
  admin.site.register(TestMe, TestMeAdmin)
  
new_contents: from django.contrib import admin
  from django_admin_bootstrapped.admin.models import SortableInline
  from .models import TestMe, TestThat, TestMeProxyForFieldsets, TestSortable
  
  
  class TestThatStackedInline(admin.StackedInline):
      model = TestThat
  
  class TestThatStackedFieldsetInline(admin.StackedInline):
      model = TestThat
      fieldsets = (
          ('A collapsed fieldset', {
              'classes': ('collapse',),
              'fields': [('test_ip', 'test_url'), 'test_date',]
          }),
      )
  
  class TestThatTabularInline(admin.TabularInline):
      model = TestThat
  
  
  class TestSortable(admin.StackedInline, SortableInline):
      model = TestSortable
      extra = 0
  
  
  class TestMeAdmin(admin.ModelAdmin):
      list_display = ['test_ip', 'test_url', 'test_int', 'test_img', 'test_file', 'test_date', 'test_char', 'test_bool', 'test_time', 'test_slug', 'test_text', 'test_email', 'test_float', 'test_bigint', 'test_positive_integer', 'test_decimal', 'test_comma_separated_int', 'test_small_int', 'test_nullbool', 'test_filepath', 'test_positive_small_int', ]
      search_fields = ['test_int', ]
      list_editable = ['test_int', ]
      list_filter = ['test_ip', 'test_url', 'test_int', ]
      list_per_page = 3
      date_hierarchy = 'test_date'
      inlines = [TestThatStackedInline, TestThatTabularInline, TestSortable]
      save_as = True
      save_on_top = True
  
  
  class TestMeAdminFieldsets(TestMeAdmin):
      actions_on_bottom = True
      inlines= [TestThatStackedFieldsetInline]
      fieldsets = (
          ('A fieldset', {
              'fields': ['test_m2m', 'test_ip', 'test_url', 'test_int', 'test_img', 'test_file', 'test_date', 'test_char', 'test_bool', 'test_time', 'test_slug', 'test_text', ],
          }),
          ('Another fieldset', {
              'fields': [('test_email', 'test_float'), 'test_bigint', ('test_positive_integer', 'test_decimal'), ('test_comma_separated_int', 'test_small_int'),],
          }),
          ('A collapsed fieldset', {
              'classes': ('collapse',),
              'fields': [('test_nullbool', 'test_filepath'), 'test_positive_small_int',]
          })
      )
  
  admin.site.register(TestMeProxyForFieldsets, TestMeAdminFieldsets)
  admin.site.register(TestMe, TestMeAdmin)
  
subject: test app: use collapsable fieldsets