can't add svg to wordpress code example

Example: allow svg wordpress

// Wp v4.7.1 and higher
add_filter( 'wp_check_filetype_and_ext', function($data, $file, $filename, $mimes) {
  $filetype = wp_check_filetype( $filename, $mimes );
  return [
      'ext'             => $filetype['ext'],
      'type'            => $filetype['type'],
      'proper_filename' => $data['proper_filename']
  ];

}, 10, 4 );

function cc_mime_types( $mimes ){
  $mimes['svg'] = 'image/svg+xml';
  return $mimes;
}
add_filter( 'upload_mimes', 'cc_mime_types' );

function fix_svg() {
  echo '<style type="text/css">
        .attachment-266x266, .thumbnail img {
             width: 100% !important;
             height: auto !important;
        }
        </style>';
}
add_action( 'admin_head', 'fix_svg' );