Further check on Monad

Signed-off-by: Yogesh Deshpande <[email protected]>

Author: yogeshbdeshpande

monad.go

@@ -74,6 +74,9 @@ func (o monad) valid() error {
 	if !o.typ.IsSet() {
 		return errors.New("type not set")
 	}
+	if o.typ.String() == "" {
+		return errors.New("invalid type")
+	}
 	return nil
 }