<https://larryullman.com/forums/index.php?/topic/29-part-3-physical-products-ch8-creating-a-catalog/#comment-158>
<http://schema.org/text>
"Okay, so you see that result if this conditional is not true: \n \nif (!$type || !$sp_type || !$sp_cat || !$category) {\n\n \n  \nSo to debug this, just before that line, I would echo out the values of those four variables. \n"
<https://larryullman.com/forums/index.php?/topic/29-part-3-physical-products-ch8-creating-a-catalog/#comment-308>