case study exercises summary python data structures empty objects tuples and named tuples named tuples dictionaries dictionary use cases using defaultdict counter lists sorting lists sets extending built-ins queues fifo queues lifo queues priority queues case study exercises summary python object-oriented shortcuts python built-in functions the len(function reversed enumerate file / placing it in context an alternative to method overloading default arguments variable argument lists unpacking arguments functions are objects too using functions as attributes callable objects case study exercises summary iii