code: func (wi WorkItem) GetLastModified() time.Time {
  	var lastModified *time.Time // default value
  	if updatedAt, ok := wi.Fields[SystemUpdatedAt].(time.Time); ok {
  		lastModified = &updatedAt
  	}
  	// also check the optional 'relationShipsChangedAt' field
  	if wi.relationShipsChangedAt != nil && (lastModified == nil || wi.relationShipsChangedAt.After(*lastModified)) {
  		lastModified = wi.relationShipsChangedAt
  	}
  
  	log.Debug(nil, map[string]interface{}{"wi_id": wi.ID}, "Last modified value: %v", lastModified)
  	return *lastModified
  }
docs: // GetLastModified returns the last modification time