response = urllib.request.urlopen(
    'https://raw.githubusercontent.com/salmanahmad/6.863/master/Labs/Assignment5/Code/wsjp.cfg'
    )
wsjp = response.read().decode('utf8')
grammar = PCFG.fromstring(wsjp)
parser = ViterbiParser(grammar)
list(parser.parse('turn off the lights'.split()))
NLTK ViterbiParser fails in parsing words that are not in the PCFG rule