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: import_job.rb
    path of file: ./repos/zammad/app/models
    
    the code of the file until where you have to start completion: # Copyright (C) 2012-2024 Zammad Foundation, https://zammad-foundation.org/

class ImportJob < ApplicationModel
  extend ::Mixin::StartFinishLogger

  store :payload
  store :result

  default_scope
    
  def start
    self.started_at = Time.zone.now
    save
    instance = name.constantize.new(self)
    instance.start
  rescue => e
    Rails.logger.error "ImportJob '#{name}' failed: #{e.message}"
    Rails.logger.error e

    # rubocop:disable Style/RedundantSelf
    if !self.result.is_a?(Hash)
      self.result = {}
    end