How to use the @pluralsight/ps-design-system-theme/react.names.dark function in @pluralsight/ps-design-system-theme

decorator: ({ themeName }) => {
    const base = css({
      overflow: 'auto',
      width: '100%',
      height: '100vh',
      transition: `background ${core.motion.speedNormal}`,
      backgroundSize: 'cover',
      background: 'transparent'
    })

    const theme = css(
      themeName === names.dark && { background: core.colors.gray06 },
      themeName === names.light && { background: core.colors.bone }
    )

    return compose(
      base,
      theme
    )
  }
}

function reset() {
    setTheme(names.dark)
  }