test
node1
BFO:0000003
occurrent
node1->node1
node2
BFO:0000015
process
node1->node2
node6
GO:0008150
biological_process
node2->node6
node3
GO:0030154
cell differentiation
node4
GO:1905177
tracheary element
differentiation
node3->node4
node5
BFO:0000001
entity
node5->node1
node7
GO:0032502
developmental process
node6->node7
node8
GO:0009987
cellular process
node6->node8
node9
GO:0048869
cellular
developmental process
node7->node9
node8->node9
node9->node3