def rule(self, left, right):
        self.dictionary[left]=right
        print(self.dictionary)
G.rule('Noun',   ('cat',))                                #  01
G.rule('Noun',   ('boy',))                                #  02
G.rule('Noun',   ('dog',))                                #  03
G.rule('Noun',   ('girl',))                               #  04
G.rule('Verb',   ('bit',))                                #  05
G.rule('Verb',   ('chased',))                             #  06
G.rule('Verb',   ('kissed',))                             #  07
G.rule('Phrase', ('the', 'Noun', 'Verb', 'the', 'Noun'))  #  08
G.rule('Story',  ('Phrase',))                             #  09
G.rule('Story',  ('Phrase', 'and', 'Story'))              #  10
G.rule('Start',  ('Story', '.'))                          #  11