APPENDIX A 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 the code for an indented code block, when within a pair of matching left and right delimiters (parentheses, square brackets, curly braces or triple quotes), or after specifying a decorator. • The$_{Ellipsis}$built-in constant. 2to3 A tool that tries to convert Python 2.x code to Python 3.x code by handling most of the incompatibilities which can be detected by parsing the source and traversing the parse tree. abstract base class Abstract base classes complement duck-typing by providing a way to define interfaces when other techniques like hasattr() would be clumsy or subtly wrong (for example with magic methods). ABCs introduce virtual subclasses, which are classes that don’t inherit from a 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$_{importlib.abc}$ module). You can create your own ABCs with the$_{abc}$module. annotation A label associated with a variable, a class attribute or a function parameter or return value, used by convention as a type hint . argument A value passed to a function (or method ) when calling the function. There are two kinds of argument: • keyword argument : an argument preceded by an identifier (e.g.$_{name=}$ ) in a function call or passed as a value in a dictionary preceded by$_{**}$ . For example,$_{3}$and$_{5}$are both keyword arguments in the following calls to$_{complex()}$ : • positional argument : an argument that is not a 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,$_{3}$ and$_{5}$are both positional arguments in the following calls: complex(3,5) complex(*(3,5)) complex(real=3, imag=5) complex(**{ 'real':3,'imag':5}) Annotations of local variables cannot be accessed at runtime, but annotations of global variables, class at- tributes, and functions are stored in the$_{__annotations__}$ special attribute of modules, classes, and func- tions, respectively. See variable annotation , function annotation , PEP 484 and PEP 526 , which describe this functionality. 2to3 is available in the standard library as lib2to3 ; a standalone entry point is provided as Tools/ scripts/2to3 . See 2to3-reference. ... Can refer to: 13