If the value that is being formatted has a digit in the position where the zero appears in the format string, that digit is copied to the result string; otherwise, a zero appears in the result string.

Developers (including you) benefit when you provide a string representation of your class. By implementing IFormattable, you can take control of this representation and provide some flexibility.

>>> def f(x: t"a{int}"): pass ... >>> import annotationlib >>> annotationlib.get_annotations(f, format=annotationlib.Format.STRING) {'x': "Template(strings=('a ...