def each_with_something( test, max=0, name=nil )
      num = 0
      child=nil
      @elements.each( name ){ |child|
        yield child if test.call(child) and num += 1
        return if max>0 and num == max
      }
    end
def each_with_something( test, max=0, name=nil )
      num = 0
      child=nil
      @elements.each( name ){ |child|
        yield child if test.call(child) and num += 1
        return if max>0 and num == max
      }
    end
A private helper method