Examples of classes that implement special operators (see reference manual):

Complex.py	Complex numbers
Dates.py	Date manipulation package by Tim Peters
Dbm.py		Wrapper around built-in dbm, supporting	arbitrary values
Range.py	Example of a generator: re-implement built-in range()
Rev.py		Yield the reverse of a sequence
Vec.py		A simple vector class
bitvec.py	A bit-vector class by Jan-Hein B\"uhrman

(For straightforward examples of basic class features, such as use of
methods and inheritance, see the library code.)