Покажите примеры конечных автоматов, которые вы используете в python. Например:

class TrackInfoHandler(object):
    def __init__(self):
        self._state="begin"
        self._acc=""

    ## ================================== Event callbacks

    def startElement(self, name, attrs):
        self._dispatch(("startElement", name, attrs))

    def characters(self, ch):
        self._acc+=ch

    def endElement(self, name):
        self._dispatch(("endElement", self._acc))
        self._acc=""

    ## ===================================
    def _missingState(self, _event):
        raise HandlerException("missing state(%s)" % self._state)

    def _dispatch(self, event):
        methodName="st_"+self._state
        getattr(self, methodName, self._missingState)(event)

    ## =================================== State related callbacks