from_http_response (OpenID::Message)

    # File lib/openid/kvpost.rb, line 31
        def self.from_http_response(response, server_url)
          msg = self.from_kvform(response.body)
          case response.code.to_i
          when 200
            return msg
          when 206
            return msg
          when 400
            raise ServerError.from_message(msg)
          else
            error_message = "bad status code from server #{server_url}: "\
            "#{response.code}"
            raise HTTPStatusError.new(error_message)
          end
        end