glossary the default python prompt of the interactive shell often seen for code examples which can be executed interactively in the interpreter the default python prompt of the interactive shell when entering code for an indented code blockwhen within pair of matching left and right delimiters (parenthesessquare bracketscurly braces or triple quotes)or after specifying decorator to tool that tries to convert python code to python code by handling most of the incompatibilities which can be detected by parsing the source and traversing the parse tree to is available in the standard library as lib to standalone entry point is provided as toolsscripts/ to see to -reference abstract base class abstract base classes complement duck-typing by providing way to define interfaces when other techniques like hasattr(would be clumsy or subtly wrong (for example with magic methodsabcs introduce virtual subclasseswhich are classes that don' inherit from class but are still recognized by isinstance(and issubclass()see the abc module documentation python comes with many built-in abcs for data structures (in the collections abc module)numbers (in the numbers module)streams (in the io module)import finders and loaders (in the importlib abc moduleyou can create your own abcs with the abc module annotation label associated with variablea class attribute or function parameter or return valueused by convention as type hint annotations of local variables cannot be accessed at runtimebut annotations of global variablesclass attributesand functions are stored in the __annotations__ special attribute of modulesclassesand functionsrespectively see variable annotationfunction annotationpep and pep which describe this functionality argument value passed to function (or methodwhen calling the function there are two kinds of argumentkeyword argumentan argument preceded by an identifier ( name=in function call or passed as value in dictionary preceded by *for example and are both keyword arguments in the following calls to complex()complex(real= imag= complex(**{'real' 'imag' }positional argumentan argument that is not keyword argument positional arguments can appear at the beginning of an argument list and/or be passed as elements of an iterable preceded by for example and are both positional arguments in the following callscomplex( complex(*( )