This is used for custom detail fields returning a QuerySet of
    admin objects.

def queryset_formatter(queryset):
    """
    This is used for custom detail fields returning a QuerySet of
    admin objects.
    """
    return Markup(
        base_list_formatter(
            None,
            [
                '<a href="{}">{}</a>'.format(u.get_admin_url(_external=True), u)
                for u in queryset
            ],
        )
    )