code: @PreAuthorize("hasAnyRole('ROLE_SU')")
    @PostMapping(value = "/add-bootstrap-theme")
    public @ResponseBody Style addBootstrapTheme(
        @RequestParam(value = "bootstrap3-style") MultipartFile bootstrap3Style,
        @RequestParam(value = "bootstrap4-style", required = false) MultipartFile bootstrap4Style)
        throws MolgenisStyleException {
      String styleIdentifier = bootstrap3Style.getOriginalFilename();
      try {
        String bs4FileName = null;
        InputStream bs3InputStream = null;
        InputStream bs4InputStream = null;
        try {
          bs3InputStream = bootstrap3Style.getInputStream();
          if (bootstrap4Style != null) {
            bs4FileName = bootstrap4Style.getOriginalFilename();
            bs4InputStream = bootstrap4Style.getInputStream();
          }
          return styleService.addStyle(
              styleIdentifier,
              bootstrap3Style.getOriginalFilename(),
              bs3InputStream,
              bs4FileName,
              bs4InputStream);
        } finally {
          if (bs3InputStream != null) {
            bs3InputStream.close();
          }
          if (bs4InputStream != null) {
            bs4InputStream.close();
          }
        }
      } catch (IOException e) {
        throw new MolgenisStyleException("unable to add style: " + styleIdentifier, e);
      }
    }
docs: Add a new bootstrap theme, theme is passed as a bootstrap css file. It is mandatory to pass a
  bootstrap3 style file but optional to pass a bootstrap 4 style file