Array has a nice feature where it can take an object and return an
array containing the object (or if the object is an Array returns the
object unchanged. So Array(1) is  but Array([1,2,3]) returns
[1,2,3]. I’d like to define a similar type of method for my own class
but have no idea how to define it. Is there a special function I must
define or is this an Array only specialty?