'Like the plaintext attribute but returns a generator'

def generate_plaintext_traceback(self):

    (yield u'Traceback    (most    recent    call    last):')
    for frame in self.frames:
        (yield (u'        File    "%s",    line    %s,    in    %s' % (frame.filename, frame.lineno, frame.function_name)))
        (yield (u'                ' + frame.current_line.strip()))
    (yield self.exception)
