- The raise statement now takes an optional argument which
specifies the traceback to be used when printing the exception's stack
trace. This must be a traceback object, such as found in
sys.exc_traceback. When omitted or given as None, the
old behavior (to generate a stack trace entry for the current stack
frame) is used.
- The tokenizer is now more tolerant of alien whitespace. Control-L in
the leading whitespace of a line resets the column number to zero,
while Control-R just before the end of the line is ignored.