def method_missing(method_name, *args, &block)
      mapped_key = key_map[method_name.to_sym]
      if attributes.has_key?(mapped_key)
        attributes[mapped_key]
      else
        super
      end
    end
def method_missing(method_name, *args, &block)
      mapped_key = key_map[method_name.to_sym]
      if attributes.has_key?(mapped_key)
        attributes[mapped_key]
      else
        super
      end
    end
Look for one of the mapped keys, and return the value or throw method missing error.