You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: fixer_workflow.go
    path of file: ./repos/cadence/service/worker/scanner/shardscanner
    
    the code of the file until where you have to start completion: // The MIT License (MIT)
//
// Copyright (c) 2017-2020 Uber Technologies Inc.
//
// Permission is hereby granted, free of charge, to any perso
    
func (fx *FixerWorkflow) Start(ctx workflow.Context) error {

	resolvedConfig := resolveFixerConfig(fx.Params.FixerWorkflowConfigOverwrites)

	var enabled CustomScannerConfig
	if supportsFixerConfig(ctx) {
		activityCtx := getShortActivityContext(ctx)
		var out FixShardConfigResults
		if err := workflow.ExecuteActivity(activityCtx, ActivityFixerConfig, FixShardConfigParams{}).Get(activityCtx, &out); err != nil {
			return err
		}
		enabled = out.EnabledInvariants
	}

	shardReportChan := workflow.GetSignalChannel(ctx, fixShardReportChan)

	for i := 0; i < resolvedConfig.Concurrency; i++ {
		idx := i
		workflow.Go(ctx, func(ctx workflow.Context) {
			batches := getCorruptedKeysBatches(resolvedConfig.ActivityBatchSize, resolvedConfig.Concurrency, fx.Keys.CorruptedKeys, idx)
			for _, batch := range batches {
				activityCtx := getLongActivityContext(ctx)
				var reports []FixReport
				if err := workflow.ExecuteActivity(activityCtx, ActivityFixShard, FixShardActivityParams{
					CorruptedKeysEntries:        batch,
					ResolvedFixerWorkflowConfig: resolvedConfig,
					EnabledInvariants:           enabled,
				}).Get(ctx, &reports); err != nil {
					errStr := err.Error()
					shardReportChan.Send(ctx, FixReportError{
						Reports:  nil,
						ErrorStr: &errStr,
					})
					return
				}
				shardReportChan.Send(ctx, FixReportError{
					Reports:  reports,
					ErrorStr: nil,
				})
			}
		})
	}

	for i := 0; i < len(fx.Keys.CorruptedKeys); {
		var reportErr FixReportError
		shardReportChan.Receive(ctx, &reportErr)
		if reportErr.ErrorStr != nil {
			return errors.New(*reportErr.ErrorStr)
		}
		for _, report := range reportErr.Reports {
			fx.Aggregator.AddReport(report)
			i++
		}
	}
	return nil
}