Update
data class Update(val path: String, val set: <Error class: unknown class>, val index: <Error class: unknown class>? = null, val key: String? = null, val equals: <Error class: unknown class>? = null) : MutationAction
Write the fields of set onto every selected element. A selector is required — this is the verb for "adjust the matching rows" — and a selector matching nothing is a no-op, never an error.