a1:
  name: a1
  sort_order: 1

b1:
  name: b1
  parent: a1
  sort_order: 1

b2:
  name: b2
  parent: a1
  sort_order: 2

# Note that the names are not alphabetically ordered:
c16:
  name: c1-six
  parent: b1
  sort_order: 6

c17:
  name: c1-seven
  parent: b1
  sort_order: 7

c18:
  name: c1-eight
  parent: b1
  sort_order: 8

c19:
  name: c1-nine
  parent: b1
  sort_order: 9

c2:
  name: c2
  parent: b2
  sort_order: 1

d2:
  name: d2
  parent: c2
  sort_order: 1

e2:
  name: e2
  parent: d2
  sort_order: 1