Add page and limit parameters to userLists(); add doc comment
Add multiple pages to mock user lists reposnses
Implement next() method for lists of lists
Add gotoPage() method
Raise exceptions for bad page requests
Next is just a version of hotoPage()
Actually, if next() is just a special instance of gotoPage(), next() should be moved into the base class (and gotoPage() should be declared abstract)
Save query string in Users object for future requests
Add gotoPage() method to Users
Add tests for bad page requests