Найдите синтаксическую ошибку Ruby: NameError: неопределенная локальная переменная или метод ` '

Вот две строки Ruby, которые проверяют, сколько элементов в массиве являются «действительными» или «недействительными»:

valid = cr.select { |x| x.valid? }.count
invalid = cr.select { |x| !x.valid? }.count

Может ли кто-нибудь определить, почему во второй строке есть синтаксическая ошибка? Я просмотрел этот код в отладчике, и при попытке выполнить строку invalid = ... возникает исключение. Единственная разница между двумя строками — это !, и я проверил, что !true == false работает. Я в тупике.

Это весь файл кода:

require "colored"

require "address_kit/cli/interactive/command"
require "address_kit/cli/interactive/shell"

module AddressKit
  module CLI
    module Interactive
      module Commands

        class TableValidationStats < TableCommand
          NAME = "table_validation_stats"
          SUMMARY = "Displays statistics about the table address validation"
          HELP_TEXT = <<-TEXT.chomp.reset_indentation
            This command displays how many rows that has been validated, how
            many of those rows were valid, invalid or auto-corrected.
          TEXT

          def execute(context, args)
            super

            shell = context.shell
            results = context.vars[:address_processing_results] || []

            if results.length < 1
              shell.puts_padded "No rows have been processed"
              return
            end

            require "byebug"; byebug

            cr = results.compact
            total_processed = cr.count
            failed_parsing = cr.select { |x| !x.parsed? }.count
            valid = cr.select { |x| x.valid? }.count
            invalid = cr.select { |x| !x.valid? }.count
            corrected = cr.select { |x| x.corrected? }.count

            shell.puts
            shell.puts "Rows processed: #{total_processed.to_s.bold}"
            shell.puts "Parse failures: #{failed_parsing.to_s.bold}"
            shell.puts "Valid addresses: #{valid.to_s.bold}"
            shell.puts "Invalid addresses: #{invalid.to_s.bold}"
            shell.puts "Addresses auto-corrected: #{corrected.to_s.bold}"
            shell.puts
          end
        end

        Shell.register_command TableValidationStats

      end
    end
  end
end

Это ошибка с трассировкой стека (не обращайте внимания на дополнительный текст, мой проект печатает информацию об ошибке вручную):

  AN ERROR HAS OCCURRED!

  The command you just ran produced an unexpected error.
  Your shell session will not be lost, but please report
  the following text to the maintainer of this project:

  Exception: NameError
  Message: undefined local variable or method ` ' for #<AddressKit::CLI::Interactive::Commands::TableValidationStats:0x00000001a6b840>

  Stack trace:
  /home/tomas/Dropbox/Kvantel/Address Kit/lib/address_kit/cli/interactive/commands/table_validation_stats.rb:37:in `block in execute'
  /home/tomas/Dropbox/Kvantel/Address Kit/lib/address_kit/cli/interactive/commands/table_validation_stats.rb:37:in `select'
  /home/tomas/Dropbox/Kvantel/Address Kit/lib/address_kit/cli/interactive/commands/table_validation_stats.rb:37:in `execute'
  /home/tomas/Dropbox/Kvantel/Address Kit/lib/address_kit/cli/interactive/shell.rb:82:in `shell_iteration'
  /home/tomas/Dropbox/Kvantel/Address Kit/lib/address_kit/cli/interactive/shell.rb:46:in `start'
  bin/address_kit_shell:42:in `<main>'

А переменная cr представляет собой массив из AddressProcessingResult объектов. Они выглядят так:

module AddressKit

  # This class represents the end result of the processing of an address,
  # including normalization, parsing, validation and correction.
  class AddressProcessingResult
    attr_accessor :original_address, :parsed_address, :corrected_address, :note
    attr_writer :parsed, :validated, :valid, :corrected

    def initialize(original_address = nil)
      @original_address = original_address
      @parsed_address = nil
      @corrected_address = nil
      @note = ""
      @parsed = false
      @validated = false
      @valid = false
      @corrected = false
    end

    def parsed?; @parsed; end
    def validated?; @validated; end
    def valid?; @valid; end
    def corrected?; @corrected; end

    def readable_summary
      if not parsed?
        "Failed to parse address: #{@original_address}"
      elsif valid?
        "Address is valid: #{@parsed_address}"
      elsif corrected?
        "Address was auto-corrected: #{@corrected_address}: #{@note}"
      else
        "Address was invalid and could not be corrected: #{@corrected_address}"
      end
    end
  end

end