```ruby
module Shoulda # :nodoc:
  module Matchers
    module ActiveRecord # :nodoc:
      module Helpers
        def pretty_error_messages(obj) # :nodoc:
          obj.errors.map do |a, m|
            msg = "#{a} #{m}"
            msg << " (#{obj.send(a).inspect})" unless a.to_sym == :base
          end
        end

        # Helper method that determines the default error message used by Active
        # Record.  Works for both existing Rails 2.1 and Rails 2.2 with the newly
        # introduced I18n module used for localization.
        #
        #   default_error_message(:blank)
        #   default_error_message(:too_short, :count => 5)
        #   default_error_message(:too_long, :count => 60)
        def default_error_message(key, values = {})
          if Object.const_defined?(:I18n) # Rails >= 2.2
            result = I18n.translate("activerecord.errors.messages.#{key}", values)
            if result =~ /^translation missing/
              I18n.translate("errors.messages.#{key}", values)
            else
              result
            end
          else # Rails <= 2.1.x
            ::ActiveRecord::Errors.default_error_messages[key] % values[:count]
          end
        end
      end
    end
  end
end
```

Change the way of translating default_error_message by using :default I18n.translation options instead of throwing I18n::MissingTranslationData
user
```ruby
module Shoulda # :nodoc:
  module Matchers
    module ActiveRecord # :nodoc:
      module Helpers
        def pretty_error_messages(obj) # :nodoc:
          obj.errors.map do |a, m|
            msg = "#{a} #{m}"
            msg << " (#{obj.send(a).inspect})" unless a.to_sym == :base
          end
        end

        # Helper method that determines the default error message used by Active
        # Record.  Works for both existing Rails 2.1 and Rails 2.2 with the newly
        # introduced I18n module used for localization.
        #
        #   default_error_message(:blank)
        #   default_error_message(:too_short, :count => 5)
        #   default_error_message(:too_long, :count => 60)
        def default_error_message(key, values = {})
          if Object.const_defined?(:I18n) # Rails >= 2.2           
            I18n.translate(:"activerecord.errors.messages.#{key}", {:default => :"errors.messages.#{key}"}.merge(values))
          else # Rails <= 2.1.x
            ::ActiveRecord::Errors.default_error_messages[key] % values[:count]
          end
        end
      end
    end
  end
end
```
assistant