'The list of files in the finalized torrent def.
@param exts (Optional) list of filename extensions (without leading .)
to search for.
@return A list of filenames.'

def get_files_with_length(self, exts=None):

    if (not self.metainfo_valid):
        raise NotYetImplementedException()
    videofiles = []
    for (filename, length) in self._get_all_files_as_unicode_with_length():
        (prefix, ext) = os.path.splitext(filename)
        if ((ext != '') and (ext[0] == '.')):
            ext = ext[1:]
        if ((exts is None) or (ext.lower() in exts)):
            videofiles.append((filename, length))
    return videofiles
