# File lib/braintree/transparent_redirect_gateway.rb, line 61
    def transaction_data(params)
      Util.verify_keys(TransactionSignature, params)
      params[:kind] = TransparentRedirect::Kind::CreateTransaction
      transaction_type = params[:transaction] && params[:transaction][:type]
      unless %w[sale credit].include?(transaction_type)
        raise ArgumentError, "expected transaction[type] of sale or credit, was: #{transaction_type.inspect}"
      end
      _data(params)
    end