for event, element in etree.iterparse(buf, events=('start', 'end')):
# Process begin and end elements
if element.get('class', '') in ('theme-begin', 'theme-end'):
for event, element in etree.iterparse(buf, events=('start', 'end')):
# Process begin and end elements
if element.get('class', '') in ('theme-begin', 'theme-end'):