add not too old filter

jdav_web/material/admin.py

@@ -1,4 +1,6 @@
 from django.contrib import admin
+from django.utils. translation import ugettext_lazy as translate
+from django.contrib.admin import SimpleListFilter
 
 from .models import MaterialPart, Ownership
 
@@ -13,10 +15,30 @@ class OwnershipInline(admin.StackedInline):
     extra = 0
 
 
+class NotTooOldFilter(SimpleListFilter):
+	title = translate('Age')
+	parameter_name = 'age'
+
+	def lookups(self, request, model_admin):
+		return (
+        	('too_old', translate('Not Too Old')),
+        	('not_too_old', translate('Too old')),
+		)
+
+	def queryset(self, request, queryset):
+		if self.value() == 'too_old':
+			return queryset.filter(pk__in=[x.pk for x in queryset.all() if x.not_too_old()])
+		if self.value() == 'not_too_old':
+			return queryset.filter(pk__in=[x.pk for x in queryset.all() if not x.not_too_old()])
+
+                           
+
 class MaterialAdmin(admin.ModelAdmin):
     """Edit view of a MaterialPart"""
 
     list_display = ('name', 'buy_date', 'lifetime', 'not_too_old', 'photo')
     inlines = [OwnershipInline]
+    list_filter = (NotTooOldFilter,)
+
 
-admin.site.register(MaterialPart, MaterialAdmin)
+admin.site.register(MaterialPart, MaterialAdmin)