Notes on Classes Data hiding is by convention Namespaces are inspectable >>> dir(sdie.SettableDie) ['__doc__', '__init__', '__module__', 'getValue', 'instances', 'roll', 'setValue'] >>> dir(s) ['__doc__', '__init__', '__module__', 'getValue', 'instances', 'roll', 'setValue', 'sides', 'value'] Attributes starting with __ are "mangled" Attributes starting and ending with __ are special hooks