I have this component:

// @flow
import React, { Element } from 'react';
import styles from './Label.scss';
import cs from 'classnames';

export const Label = ({
  id,
  htmlFor,
  invalid,
  required,
  children
}: {
  id: string,
  htmlFor: string,
  invalid: boolean,
  required: boolean,
  children: Element<*>
}) =>
  <label
    htmlFor={htmlFor}
    id={id}
    required={required}
    className={cs(