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: customer.rb
    path of file: ./repos/openfoodnetwork/lib/reporting/reports/packing
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Reporting
  module Reports
    module Packing
      class Customer < Base
        def columns
          # Reorder default columns
          super.slice(:hub, :customer_code, :first_name, :last_name, :phone,
                      :supplier, :produ
    
        def rules
          [
            {
              group_by: :hub,
              header: true,
              header_class: "h1 with-background text-center",
            },
            {
              group_by: proc { |_item, row| row_header(row) },
              header: true,
              fields_used_in_header: [:first_name, :last_name, :customer_code, :phone],
              summary_row:,
            }
          ]
        end