code: def to_param
        params = to_hash.merge(
          'callerKey' => AmazonFlexPay.access_key,
          'signatureVersion' => 2,
          'signatureMethod' => 'HmacSHA256'
        )
        params['signature'] = AmazonFlexPay.sign(AmazonFlexPay.pipeline_endpoint, params)
        AmazonFlexPay::Util.query_string(params)
      end
docs: Converts the Pipeline object into parameters and signs them.