public function block(block_contents $bc, $region) {
        $bc = clone($bc); // Avoid messing up the object passed in.
        if (empty($bc->blockinstanceid) || !strip_tags($bc->title)) {
            $bc->collapsible = block_contents::NOT_HIDEABLE;
        }

        $id = !empty($bc->attributes['id']) ? $bc->attributes['id'] : uniqid('block-');
        $context = new stdClass();
        $context->skipid = $bc->skipid;
        $context->blockinstanceid = $bc->blockinstanceid;
        $context->dockable = $bc->dockable;
        $context->id = $id;
        $context->hidden = $bc->collapsible == block_contents::HIDDEN;
        $context->skiptitle = strip_tags($bc->title);
        $context->showskiplink = !empty($context->skiptitle);
        $context->arialabel = $bc->arialabel;
        $context->ariarole = !empty($bc->attributes['role']) ? $bc->attributes['role'] : 'complementary';
        $context->type = $bc->attributes['data-block'];
        $context->title = $bc->title;
        $context->content = $bc->content;
        $context->annotation = $bc->annotation;
        $context->footer = $bc->footer;
        $context->hascontrols = !empty($bc->controls);
        if ($context->hascontrols) {
            $context->controls = $this->block_controls($bc->controls, $id);
        }

        return $this->render_from_template('core/block', $context);
    }