list of names which is going to be checked
true if all the names in the list is unique and not empty
Examples: Test of the isUnique
string[] names; assert(names.isUnique); names = [null, "test"]; assert(!names.isUnique); names = ["test", "test"]; assert(!names.isUnique); names = ["test", "test1"]; assert(names.isUnique); names = ["test", "test1", "test"]; assert(!names.isUnique);