'Select which files in the torrent to download. The filenames must
be the names as they appear in the content def, including encoding.
Trivially, when the torrent contains a file \'sjaak.avi\' the files
parameter must be \'sjaak.avi\'. When the content def is a torrent def
and contains multiple files and is named \'filecollection\', the files
parameter must be
os.path.join(\'filecollection\',\'sjaak.avi\')
For a swift def, the files must be following the multi-file spec encoding
(i.e., UTF-8 and /).
@param files Can be a single filename or a list of filenames (e.g.
[\'harry.avi\',\'sjaak.avi\']). Not Unicode strings!'

def set_selected_files(self, files):

    if isinstance(files, StringType):
        files = [files]
    if ((self.get_mode() == DLMODE_VOD) and (len(files) > 1)):
        raise ValueError('In    Video-On-Demand    mode    only    1    file    can    be    selected    for    download')
    self.dlconfig.set('download_defaults', 'selected_files', files)
