Example with mandatory variables not filled in

variable: example             # A variable
family:                       # A family
  variable1: example          # A first variable
  subfamily:                  # A sub family
    variable: example         # A variable
  variable2: example          # A second variable

Example with all variables modifiable

variable: example             # A variable
family:                       # A family
  variable1: example          # A first variable
  subfamily:                  # A sub family
    variable: example         # A variable
  variable2: example          # A second variable