Subclass Python list to Validate New Items

Question

I want a python list which represents itself externally as an average of its internal list items, but otherwise behaves as a list. It should raise a TypeError i

Answer 1

The general approach would be to create your own class inheriting vom list and overwriting the specific methods like append, extend etc. This will probably also include magic methods of the Python list (see this article for details: http://www.rafekettler.com/magicmethods.html#sequence).

For validation, you will need to overwrite __setitem__(self, key, value)