rem: g_return_if_fail (GST_IS_ELEMENT (bvw->priv->play));
context: bacon_video_widget_set_aspect_ratio (BaconVideoWidget *bvw,				BaconVideoWidgetAspectRatio ratio){  g_return_if_fail (bvw != NULL);  g_return_if_fail (BACON_IS_VIDEO_WIDGET (bvw));  g_return_if_fail (GST_IS_ELEMENT (bvw->priv->play));}