How to use the ln-service.decodePaymentRequest function in ln-service

decodedRequest: ['getLnd', 'getPrices', ({getLnd, getPrices}, cbk) => {
        return decodePaymentRequest({
          lnd: getLnd.lnd,
          request: getPrices.request,
        },
        cbk);
      }],

to: ['validate', ({}, cbk) => {
      if (!!args.destination) {
        return cbk(null, {destination: args.destination, routes: []});
      }

      if (!args.request) {
        return cbk([400, 'PayRequestOrDestinationRequiredToInitiateProbe']);
      }

      return decodePaymentRequest({lnd: args.lnd, request: args.request}, cbk);
    }],

decodeExecutionRequest: ['initiateSwap', ({initiateSwap}, cbk) => {
      if (!!args.recovery) {
        return cbk();
      }

      return decodePaymentRequest({
        lnd: args.lnd,
        request: initiateSwap.swap_execute_request,
      },
      cbk);
    }],