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: printify_stripe_e_commerce.rb
    path of file: ./repos/violet_rails/plugins/installers
    
    the code of the file until where you have to start completion: SHOPS_TO_SYNC = [ENV['SHOP_NAME']]

p "*** [FAILED]: PLEASE PROVIDE SHOP_NAME TO CONTINUE  ***" and return if ENV['SHOP_NAME'].nil?

PRINTIFY_API_KEY = ENV['PRINTIFY_API_KEY']

p "*** [FAILED]: PLEASE PROVIDE PRINTIFY_API_KEY TO CONTINUE  ***" and return if PRINTIFY_API_KEY.nil?

STRIPE_SECRET_KEY = ENV['STRIPE_SECRET_KEY']

BUSINESS_NAME = ENV['BUSINESS_NAME'] || 'My Printify Account'

PRODUCTS_PAGE_SLUG = ENV['PRODUCTS_PAGE_SLUG'] || 'products'

WEBHOOK_SECRET = SecureRandom.hex

PRODUCT_CATEGORIES = ["Men's Clothing", "Women's Clothing", "Home & Living", "Accessories", "Kids' Clothing"]

PRODUCT_SUB_CATEGORIES = ["T-shirts", "Hoodies", "Swea
    
                      def start
                        begin
                          shops = @external_api_client.api_namespace.api_resources
                          shops_detail = []
                    
                          shops.each do |shop|
                            shops_detail << {
                              shop_id: shop.properties['printify_shop_id'],
                              currency: shop.properties['currency'],
                              collect_sales_tax: shop.properties['collect_sales_tax'],
                              pass_processing_fees_to_customer: shop.properties['pass_processing_fees_to_customer'],
                              shipping_countries: shop.properties['shipping_countries']
                            }
                          end
                    
                          render json: {
                            success: true,
                            data: {
                              shops_detail: shops_detail
                            }
                          }
                    
                        rescue => e
                          log_error('shipping_countries_list', e.message, @payload)
                    
                          render json: {
                            success: false,
                            message: e.message
                          }, status: :bad_request
                        end