fields:
- name: A Top
type: Nested
constraints:
- type: IfNull
name: B Top.B Nested
- name: B Top
type: Nested
fields:
- name: B Nested
type: Nested
null_probability: 0.5
- name: C List
type: Nested
args:
subtype: List
fields:
- name: C Nested 1
type: Digit
- name: C Nested 2
type: String