How do you tell which category the property belongs to？ : <pre><code>typealias Names = String
typealias Works = String

let a: Names = Names()
let b: Works = Works()

if a is Names {// a is not Works
}

</code></pre>

<p>How do I know if "a" belongs to "Names" instead of "Works"?</p>

<p>Thanks!</p>
