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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def build(cls, root, schema, filter=('*',)):
 """ Build an xsobject representation. @param root: An schema XML root. @type root: L{sax.element.Element} @param filter: A tag filter. @return: A schema object graph. @rtype: L{sxbase.SchemaObject} """

        children = []
        for node in root.getChildren(ns=Namespace.xsdns):
            if '*' in filter or node.name in filter:
                child = cls.create(node, schema)
                if child is None:
                    continue
                children.append(child)
                c = cls.build(node, schema, child.childtags())
                child.rawchildren = c
        return children