>>> wn.synsets('computer')
[Synset('computer.n.01'), Synset('calculator.n.01')]
>>> wn.synset('computer.n.01').lemmas
<bound method Synset.lemmas of Synset('computer.n.01')>
>>> wn.lemma('computer.n.01')
Traceback (most recent call last):
  File "<pyshell#66>", line 1, in <module>
    wn.lemma('computer.n.01')
  File "C:\Program Files\Python3.6.2\lib\site-packages\nltk\corpus\reader\wordnet.py", line 1281, in lemma
    separator = SENSENUM_RE.search(name).end()
AttributeError: 'NoneType' object has no attribute 'end'
>>> wn.lemma('computer.n.01').synset
Traceback (most recent call last):
  File "<pyshell#67>", line 1, in <module>
    wn.lemma('computer.n.01').synset
  File "C:\Program Files\Python3.6.2\lib\site-packages\nltk\corpus\reader\wordnet.py", line 1281, in lemma
    separator = SENSENUM_RE.search(name).end()
AttributeError: 'NoneType' object has no attribute 'end'
>>> wn.lemma('computer.n.01').name
Traceback (most recent call last):
  File "<pyshell#68>", line 1, in <module>
    wn.lemma('computer.n.01').name
  File "C:\Program Files\Python3.6.2\lib\site-packages\nltk\corpus\reader\wordnet.py", line 1281, in lemma
    separator = SENSENUM_RE.search(name).end()
AttributeError: 'NoneType' object has no attribute 'end'

>>> wn.lemmas('computer')
[Lemma('computer.n.01.computer'), Lemma('calculator.n.01.computer')]