This endpoint will return a listing of all available email lists for a given site.
GET /lists/
[
{'id': 'JWMBkGx', 'name': 'Demo Newsletter List'},
{'id': 'pDvez0G', 'name': 'Test New List'},
{'id': 'k9BZe9O', 'name': 'Unsubscribed Customers'}
]