# File lib/rhc/core_ext.rb, line 200
    def transform_keys!(operation)
      keys.each do |key|
        v = delete(key)
        if v.is_a? Hash
          v.transform_keys!(operation)
        elsif v.is_a? Array
          v.each{ |value| value.transform_keys!(operation) if value.is_a? Hash }
        end
        self[(key.send(operation) rescue key) || key] = v
      end
      self
    end