{α : Type} →
  {motive : Lean.KVMap.Value α → Sort u} →
    ((toDataValue : α → Lean.DataValue) →
        (ofDataValue? : Lean.DataValue → Option α) →
          motive { toDataValue := toDataValue, ofDataValue? := ofDataValue? }) →
      (t : Lean.KVMap.Value α) → motive t