A format string consists of zero or more "format units."A format unit describes one Python object; it is usually a single character or a parenthesized sequence of format units.With a few exceptions, a format unit that is not a parenthesized sequence normally corresponds to a single address argument to these functions.In the following description, the quoted form is the format unit; the entry in (round) parentheses is the Python object type that matches the format unit; and the entry in [square] brackets is the type of the C variable(s) whose address should be passed.