is_staff isn’t a permission so instead of permission_required you could use:
@user_passes_test(lambda u: u.is_staff)
or
from django.contrib.admin.views.decorators import staff_member_required
@staff_member_required
is_staff isn’t a permission so instead of permission_required you could use:
@user_passes_test(lambda u: u.is_staff)
or
from django.contrib.admin.views.decorators import staff_member_required
@staff_member_required