test
node1
GO:0008152
metabolic process
node2
GO:0071704
organic substance
metabolic process
node1->node2
node3
GO:0008150
biological_process
node3->node1
node4
BFO:0000015
process
node4->node3
node5
BFO:0000001
entity
node6
BFO:0000003
occurrent
node5->node6
node6->node4
node6->node6