parent_part	part	part_occs	return
Part-tag-2 (Axle)	Part-tag-1 (Wheel)	Part_occur-tag_1	2
		Part_occur-tag-2
Part-tag-3 (Auto)	Part-tag-1(Wheel)	Part_occur-tag-5	5
		Part_occur-tag-6
		Part_occur-tag-7
		Part_occur-tag-8
		Part_occur-tag-6