# File lib/paperclip/missing_attachment_styles.rb, line 66
  def self.missing_attachments_styles
    current_styles = current_attachments_styles
    registered_styles = get_registered_attachments_styles

    Hash.new.tap do |missing_styles|
      current_styles.each do |klass, attachment_definitions|
        attachment_definitions.each do |attachment_name, styles|
          registered = registered_styles[klass][attachment_name] || [] rescue []
          missed = styles - registered 
          if missed.present?
            klass_sym = klass.to_s.to_sym
            missing_styles[klass_sym] ||= Hash.new
            missing_styles[klass_sym][attachment_name.to_sym] ||= Array.new
            missing_styles[klass_sym][attachment_name.to_sym].concat(missed.to_a)
            missing_styles[klass_sym][attachment_name.to_sym].map!(&:to_s).sort!.map!(&:to_sym).uniq!
          end
        end
      end  
    end
  end