test
node1
GO:0043473
pigmentation
node2
GO:0033059
cellular pigmentation
node1->node2
node3
BFO:0000015
process
node4
GO:0008150
biological_process
node3->node4
node4->node1
node5
GO:0009987
cellular process
node4->node5
node5->node2
node6
BFO:0000003
occurrent
node6->node3
node7
BFO:0000001
entity
node7->node6