Sets the dataPath for the parent

[shihuili1218]

data class Baby(
    val age: Int
)

The current error message is '. age must be less than 5 '. I add Baby before .age. e.g: 'Baby. age must be less than 5'

[shihuili1218]

@nlochschmidt @sksamuel @jillesvangurp @wtomi

Could you please give me some guidance？