'A list of rules based on context (preceding and following words).'

def __init__(self, lexicon={}, path=u''):

    cmd = (u'prevtag', u'nexttag', u'prev2tag', u'next2tag', u'prev1or2tag', u'next1or2tag', u'prev1or2or3tag', u'next1or2or3tag', u'surroundtag', u'curwd', u'prevwd', u'nextwd', u'prev1or2wd', u'next1or2wd', u'next1or2or3wd', u'prev1or2or3wd', u'prevwdtag', u'nextwdtag', u'wdprevtag', u'wdnexttag', u'wdand2aft', u'wdand2tagbfr', u'wdand2tagaft', u'lbigram', u'rbigram', u'prevbigram', u'nextbigram')
    Rules.__init__(self, lexicon, dict.fromkeys(cmd, True))
    self._path = path
