def define_attr_logger_attribute(attribute)
      instance_variable_set(:"@#{attribute}", []) unless instance_variable_get(:"@#{attribute}")
      return if instance_variable_get(:"@#{attribute}").respond_to?(:<<)
      raise InvalidAttributeValue, "invalid type for attribute #{attribute}: #{send(attribute).class}"
    end
def define_attr_logger_attribute(attribute)
      instance_variable_set(:"@#{attribute}", []) unless instance_variable_get(:"@#{attribute}")
      return if instance_variable_get(:"@#{attribute}").respond_to?(:<<)
      raise InvalidAttributeValue, "invalid type for attribute #{attribute}: #{send(attribute).class}"
    end
ensure the attribute itself has been initialized...