One of the ProgrammingParadigm

 * http://www.onlamp.com/pub/a/python/2003/04/17/metaclasses.html
 * [[http://www.artima.com/forums/flat.jsp?forum=106&thread=236234|Metaclass programming in Python3.0]]
 * [[http://agiliq.com/blog/2012/07/metaclass-python/|Metaclass in Python]]