def exc_info():
le = JS('$pyjs.__last_exception__')
if not le:
return (None, None, None)
if not hasattr(le.error, '__class__'):
cls = None
else:
cls = le.error.__class__
tb = JS('$pyjs.__last_exception_stack__')
if tb:
start = tb.start
while tb and start > 0:
tb = tb.tb_next
start -= 1
else:
tb = le
tb.tb_next = None
return (cls, le.error, tb)
