Summary: extend python's abstract syntax tree
Author: Sylvain Thenault
Description: The aim of this module is to provide a common base representation of
python source code for projects such as pychecker, pyreverse,
pylint... Well, actually the development of this library is essentialy
governed by pylint's needs.
It extends class defined in the compiler.ast  module with some
additional methods and attributes. Instance attributes are added by a
builder object, which can either generate extended ast (let's call
them astng ;) by visiting an existant ast tree or by inspecting living
object. Methods are added by monkey patching ast classes.