def pm(frameno=<NUM_LIT:1>, dbg=None):
post_mortem(get_last_or_frame_exception(), frameno, dbg=dbg)<EOL>return<EOL>
Set up post-mortem debugging using the last traceback.  But if
    there is no traceback, we'll assume that sys.exc_info() contains
    what we want and frameno is the index location of where we want
    to start.

    'dbg', is an optional trepan.Trepan object.