lambda functions assertions examplemake_html_skeleton py summary exercise modules modules and packages packages custom modules overview of python' standard library string handling command-line programming mathematics and numbers times and dates algorithms and collection data types file formatsencodingsand data persistence filedirectoryand process handling networking and internet programming xml other modules summary exercise object-oriented programming the object-oriented approach object-oriented concepts and terminology custom classes attributes and methods inheritance and polymorphism using properties to control attribute access creating complete fully integrated data types custom collection classes creating classes that aggregate collections creating collection classes using aggregation creating collection classes using inheritance summary exercises xi