class AWS::Record::ExclusionValidator

def message
  options[:message] || 'is reserved'
end

def setup record_class
  ensure_present(:in)
  ensure_type(Enumerable, :in)
end

def validate_attribute record, attribute_name, value_or_values
  each_value(value_or_values) do |value|
    included = value_included?(value)
    record.errors.add(attribute_name, message) if included 
  end
end