docs: def from_file(cls, paramname, filename):
          """Returns a new MultipartParam object constructed from the local
          file at ``filename``.
  
          ``filesize`` is determined by os.path.getsize(``filename``)
  
          ``filetype`` is determined by mimetypes.guess_type(``filename``)[0]
  
          ``filename`` is set to os.path.basename(``filename``)
          """
  
          return cls(paramname, filename=os.path.basename(filename),
                     filetype=mimetypes.guess_type(filename)[0],
                     filesize=os.path.getsize(filename),
                     fileobj=open(filename, "rb"))