---
rootElement1: { presence: required, structure: {
  field11: {
    presence: required,
    value: [X, Y, Z],
    comment: "field 11 description"
  },
  field12: {
    presence: required,
    comment: "field 12 description"
  }
}}
rootElement2: { presence: required, structure: {
  field21: {
    presence: required,
    value: [22, 222, 2222],
    comment: "field 21 description"
  },
  field22: {
    presence: optional,
    value: [ A,B,C ],
    comment: "field 22 description"
  }
}}
rootElement3: { presence: optional, structure: {
  field3: {
    presence: required,
    comment: "field 3 description"
  }
}}
...
---
rootElement1:
  field11: X
  field12: test
rootElement2:
  field21: 22
  field22: B
...
---
rootElement1:
  field11: X
  field12: test12
rootElement2:
  field21: 22
rootElement3:
  field3: test3
...
---
rootElement1:
  field11: Y
  field12: testing12
rootElement2:
  field21: 222
  field22: A
rootElement3:
  field3: testing3
...