class MultiXml::Parsers::Ox::Handler

def append(key, value)
  key = key.to_s
  h = @stack.last
  if h.has_key?(key)
    v = h[key]
    if v.is_a?(Array)
      v << value
    else
      h[key] = [v, value]
    end
  else
    h[key] = value
  end
end