as opposed to the cleanerpythonic methodfor piece in foodprint(piecequalified name dotted name showing the "pathfrom module' global scope to classfunction or method defined in that moduleas defined in pep for top-level functions and classesthe qualified name is the same as the object' nameclass cclass ddef meth(self)pass __qualname__ 'cc __qualname__ ' dc meth __qualname__ ' methwhen used to refer to modulesthe fully qualified name means the entire dotted path to the moduleincluding any parent packagese email mime textimport email mime text email mime text __name__ 'email mime textreference count the number of references to an object when the reference count of an object drops to zeroit is deallocated reference counting is generally not visible to python codebut it is key element of the cpython implementation the sys module defines getrefcount(function that programmers can call to return the reference count for particular object regular package traditional packagesuch as directory containing an __init__ py file see also namespace package __slots__ declaration inside class that saves memory by pre-declaring space for instance attributes and eliminating instance dictionaries though popularthe technique is somewhat tricky to get right and is best reserved for rare cases where there are large numbers of instances in memory-critical application sequence an iterable which supports efficient element access using integer indices via the __getitem__(special method and defines __len__(method that returns the length of the sequence some built-in sequence types are liststrtupleand bytes note that dict also supports __getitem__(and __len__()but is considered mapping rather than sequence because the lookups use arbitrary immutable keys rather than integers the collections abc sequence abstract base class defines much richer interface that goes beyond just __getitem__(and __len__()adding count()index()__contains__()and __reversed__(types that implement this expanded interface can be registered explicitly using register(single dispatch form of generic function dispatch where the implementation is chosen based on the type of single argument slice an object usually containing portion of sequence slice is created using the subscript notation[with colons between numbers when several are givensuch as in variable_name[ : : the bracket (subscriptnotation uses slice objects internally