# File kwartz.rb, line 1046
        def find_with_parent(parent=nil, &block)
            return self, parent if yield(self)
            [@condition, @left, @right].each do |child|
                if child && child.is_a?(Node)
                    ret = child.find_with_parent(self, &block)
                    return ret if ret
                end
            end
            return nil
        end