render(
  <Box>
    <Select multiple>
      <Select.OptionGroup title="Group 1">
        <Select.Option value="1">One</Select.Option>
        <Select.Option value="2">Two</Select.Option>
        <Select.Option value="3">Three</Select.Option>
      </Select.OptionGroup>
      <Select.OptionGroup title="Group 2">
        <Select.Option value="4">Four</Select.Option>
        <Select.Option value="5">Five</Select.Option>
        <Select.Option value="6">Six</Select.Option>
      </Select.OptionGroup>
    </Select>
  </Box>
)