s $=[1,\text{'}$a$\text{'},3]$

represents the mathematical set object $\{1,\text{'}$a$\text{'},3\}.$

Note that since order does not matter, the same set can be represented by a list that has the elements of the set in a different order. In your implementation, the result returned by your code should not depend on the order in which the elements appear in the list.

Your job is to implement the following set operations