How to use the webcoach.pickAPage function in webcoach

'The coach got the following errors: ' +
                      JSON.stringify(coachAdvice.errors),
                    {
                      url,
                      runIndex,
                      iteration: runIndex + 1
                    }
                  )
                );
              }

              let advice = coachAdvice;
              // If we run without HAR
              if (result.har) {
                // make sure to get the right run in the HAR
                const myHar = api.pickAPage(result.har, harIndex);
                const harResult = await api.runHarAdvice(myHar);
                advice = api.merge(coachAdvice, harResult);
              }
              queue.postMessage(
                make('coach.run', advice, {
                  url,
                  group,
                  runIndex,
                  iteration: runIndex + 1
                })
              );
            }

            aggregator.addToAggregate(run, group);
            runIndex++;
          }

`${
                        options.resultDir
                      }/${this.resultUrls.relativeSummaryPageUrl(url)}`,
                      this.allOptions,
                      `${base}data/filmstrip/${runIndex + 1}/`
                    );
                  }
                }
              } else {
                log.error(
                  'Could not find the right index %s for har for url %s ',
                  harIndex,
                  url
                );
              }
              run.har = api.pickAPage(result.har, harIndex);
            }

            // Hack to get axe data. In the future we can make this more generic
            if (result[resultIndex].extras.length > 0) {
              if (result[resultIndex].extras[runIndex].axe) {
                const order = ['critical', 'serious', 'moderate', 'minor'];
                result[resultIndex].extras[runIndex].axe.violations.sort(
                  (a, b) => order.indexOf(a.impact) > order.indexOf(b.impact)
                );

                axeAggregatorPerURL.addStats(
                  result[resultIndex].extras[runIndex].axe
                );

                this.axeAggregatorTotal.addStats(
                  result[resultIndex].extras[runIndex].axe