array (
  'text' =>
  array (
    'html' => 'html',
    'plain' => 'plain',
    'richtext' => 'richtext',
    'xml' => 'xml',
  ),
  'image' =>
  array (
    'jpeg' => 'jpeg',
    'bmp' => 'bmp',
    'gif' => 'gif',
    'png' => 'png',
    'tiff' => 'tiff',
    'x-wmf' => 'x-wmf',
  ),
  'video' =>
  array (
    'mpeg' => 'mpeg',
    'avi' => 'avi',
    'x-pn-realvideo' => 'x-pn-realvideo',
    'quicktime' => 'quicktime',
    's-pn-realvideo-plugin' => 's-pn-realvideo-plugin',
  ),
  'audio' =>
  array (
    'mp3' => 'mp3',
    'basic' => 'basic',
    'midi' => 'midi',
    'x-pn-realaudio' => 'x-pn-realaudio',
    'x-pn-realaudio-plugin' => 'x-pn-realaudio-plugin',
    'x-wav' => 'x-wav',
    'mpeg' => 'mpeg',
  ),
  'application' =>
  array (
    'pdf' => 'pdf',
    'base64' => 'base64',
    'binary' => 'binary',
    'java' => 'java',
    'macbinhex40' => 'macbinhex40',
    'msexcel' => 'msexcel',
    'msword' => 'msword',
    'ogg' => 'ogg',
    'postscript' => 'postscript',
    'ppt' => 'ppt',
    'rtf' => 'rtf',
    'uue' => 'uue',
    'x-compressed' => 'x-compressed',
    'x-gzip-compressed' => 'x-gzip-compressed',
    'zip' => 'zip',
  ),
  'model' =>
  array (
    'vrml' => 'vrml',
  ),
  'non_digital' => 'non digital',
)