macintosh convention '\rsee pep and pep as well as bytes splitlines(for an additional use variable annotation an annotation of variable or class attribute when annotating variable or class attributeassignment is optionalclass cfield'annotationvariable annotations are usually used for type hintsfor example this variable is expected to take int valuescountint variable annotation syntax is explained in section annassign see function annotationpep and pep which describe this functionality virtual environment cooperatively isolated runtime environment that allows python users and applications to install and upgrade python distribution packages without interfering with the behaviour of other python applications running on the same system see also venv virtual machine computer defined entirely in software python' virtual machine executes the bytecode emitted by the bytecode compiler zen of python listing of python design principles and philosophies that are helpful in understanding and using the language the listing can be found by typing "import thisat the interactive prompt