test
node1
BFO:0000003
occurrent
node1->node1
node6
BFO:0000015
process
node1->node6
node2
GO:0008150
biological_process
node3
GO:0008152
metabolic process
node2->node3
node5
GO:0018933
nicotine metabolic
process
node3->node5
node4
BFO:0000001
entity
node4->node1
node6->node2