How to add this css class to react?

I used classnames package as a tutorial but it doesn’t work.
Here is an error

Uncaught DOMException: Failed to execute ‘add’ on ‘DOMTokenList’: The token provided (‘skin-blue hold-transition sidebar-mini’) contains HTML space characters, which are not valid in tokens.

Here is a code

  render() {
    const bodyClassName = classnames(
        'skin-blue': true,
        'hold-transition': true,
        'sidebar-mini': true,
    return <div style={styles.root}>
      <ReactBody className={bodyClassName}/>

How to solve this problem?