def set_label(self, infohash_list, label):
data = self._process_infohash_list(infohash_list)<EOL>data['<STR_LIT:label>'] = label<EOL>return self._post('<STR_LIT>', data=data)<EOL>
Set the label on multiple torrents.
IMPORTANT: OLD API method, kept as it is to avoid breaking stuffs.

:param infohash_list: Single or list() of infohashes.