test
node1
GO:0008150
biological_process
node2
GO:0008152
metabolic process
node1->node2
node3
GO:0042440
pigment metabolic
process
node2->node3
node4
GO:0046148
pigment biosynthetic
process
node3->node4
node5
BFO:0000003
occurrent
node5->node5
node6
BFO:0000015
process
node5->node6
node6->node1
node7
BFO:0000001
entity
node7->node5