bKc@sdZiZddZdS(soA collection of modules for building different kinds of tree from HTML documents. To create a treebuilder for a new type of tree, you need to do implement several things: 1) A set of classes for various types of elements: Document, Doctype, Comment, Element. These must implement the interface of _base.treebuilders.Node (although comment nodes have a different signature for their constructor, see treebuilders.simpletree.Comment) Textual content may also be implemented as another node type, or not, as your tree implementation requires. 2) A treebuilder object (called TreeBuilder by convention) that inherits from treebuilders._base.TreeBuilder. This has 4 required attributes: documentClass - the class to use for the bottommost node of a document elementClass - the class to use for HTML Elements commentClass - the class to use for comments doctypeClass - the class to use for doctypes It also has one required method: getDocument - Returns the root node of the complete document tree 3) If you wish to run the unit tests, you must also create a testSerializer method on your treebuilder which accepts a node and returns a string containing Node and its children serialized according to the format used in the unittests The supplied simpletree module provides a python-only implementation of a full treebuilder and is a useful reference for the semantics of the various methods. c Ks|j}|tkr|dkrhddl}|dkrUddlm}|}n|j||jS|dkrddl}|jt|s