Method is

packages/effect/src/Brand.ts:110–110

* Attempts to refine the provided value of type `A`, returning `true` if * the provided `A` is valid, `false` otherwise.

(a: Brand.Unbranded<A>)

     * the provided `A` is valid, `false` otherwise.
     */
    is(a: Brand.Unbranded<A>): a is Brand.Unbranded<A> & A
  }

  /**