code: def guess_mimetype(filename):
      
      fn = os.path.basename(filename)
      return mimetypes.guess_type(fn)[0] or 'application/octet-stream'
docs: Guesses the mimetype of a file based on the given ``filename``.
  
      .. code-block:: python
  
          >>> guess_mimetype('example.txt')
          'text/plain'
          >>> guess_mimetype('/foo/bar/example')
          'application/octet-stream'
  
      Parameters
      ----------
      filename : str
          The file name or path for which the mimetype is to be guessed