old_contents: from django.contrib import admin
  
  from coding.models import (
          Sample, AssignmentTag, CodingAssignment, CodingAssignmentActivity)
  
  
  class SampleAdmin(admin.ModelAdmin):
      filter_horizontal = ("pieces",)
  
  admin.site.register(Sample, SampleAdmin)
  
  
  class AssignmentTagAdmin(admin.ModelAdmin):
      list_filter = ("study",)
      list_display = ("name",  "study",)
  
  admin.site.register(AssignmentTag, AssignmentTagAdmin)
  
  
  class CodingAssignmentAdmin(admin.ModelAdmin):
      list_filter = ("coder", "tags", "piece__tags", "sample", "state")
      list_display = (
              "piece",  "coder",
              "sample", "state", "creation_time")
  
      search_fields = ("piece__id", "piece__title", "sample__name")
  
      filter_horizontal = ("tags",)
  
  admin.site.register(CodingAssignment, CodingAssignmentAdmin)
  
  
  class CodingAssignmentActivityAdmin(admin.ModelAdmin):
      search_fields = (
              "assignment__piece__id",
              "assignment__piece__title",
              "actor__name",
              )
  
      list_display = ("assignment", "action_time", "actor", "action", "state")
      list_filter = ("actor", "action", "state")
  
  admin.site.register(CodingAssignmentActivity, CodingAssignmentActivityAdmin)
  
new_contents: from django.contrib import admin
  
  from coding.models import (
          Sample, AssignmentTag, CodingAssignment, CodingAssignmentActivity)
  
  
  class SampleAdmin(admin.ModelAdmin):
      filter_horizontal = ("pieces",)
  
  admin.site.register(Sample, SampleAdmin)
  
  
  class AssignmentTagAdmin(admin.ModelAdmin):
      list_filter = ("study",)
      list_display = ("name",  "study",)
  
  admin.site.register(AssignmentTag, AssignmentTagAdmin)
  
  
  class CodingAssignmentAdmin(admin.ModelAdmin):
      list_filter = ("coder", "tags", "piece__tags", "sample", "state")
      list_display = (
              "piece",  "coder",
              "sample", "state", "creation_time")
  
      search_fields = ("piece__id", "piece__title", "sample__name")
  
      filter_horizontal = ("tags",)
  
  admin.site.register(CodingAssignment, CodingAssignmentAdmin)
  
  
  class CodingAssignmentActivityAdmin(admin.ModelAdmin):
      search_fields = (
              "assignment__piece__id",
              "assignment__piece__title",
              "actor__name",
              )
  
      list_display = ("assignment", "action_time", "actor", "action", "state")
      list_filter = ("actor", "action", "state")
  
      date_hierarchy = "action_time"
  
  admin.site.register(CodingAssignmentActivity, CodingAssignmentActivityAdmin)
  
subject: Add date drill down to coding assignment activity list