Как в NLTK получить согласованность текста?

>>> c = t.concordance('president')
Displaying 25 of 142 matches:
of Hays , Kan. as the school's new president . Dr. Clark will succeed Dr. J. R.
 dollars , said C. Virgil Martin , president of Carson Pirie Scott & Co. , comm
dants '' . Washington , July 24 -- president Kennedy today pushed aside other W
ionwide television and radio . The president spent much of the week-end at his 
drafts '' . Salinger said the work president Kennedy , advisers , and members o
miss them . Washington , Feb. 9 -- president Kennedy today proposed a mammoth n
railroad retirement programs . The president , in a special message to Congress
ged care plan , similar to one the president sponsored last year as a senator ,
or up to 240 days an illness . The president noted that Congress last year pass
e medical and dental schools . The president said the nation's 92 medical and 4
go up to 21 millions by 1966 . The president recommended federal `` matching gr
community health services '' , the president called for doubling the present 10
 . In the child health field , the president said he will recommend later an in
nstitute . Asks research funds The president said he will ask Congress to incre
building research facilities . The president said he will also propose increasi
ernment research in medicine . The president said his proposals combine the `` 
e ( D. , Ore. ) in connection with president Eisenhower's cabinet selections in
r's cabinet selections in 1953 and president Kennedy's in 1961 . Oslo The most 
e was critical of what he feels is president Kennedy's tendency to be too conci
cation . But he did recommend that president Kennedy state clearly that if Comm
 any observer would have said that president Kennedy had blended a program that
nquency in the United States . The president is deeply concerned over this prob
orities on juvenile problems . The president asks the support and cooperation o
rime trend . Offenses multiply The president has also called upon the Attorney 
h the problem . Simultaneously the president announced Thursday the appointment
>>> print c
None

Но я не могу установить его в переменную ... Я хочу иметь возможность установить его в переменную, чтобы я мог что-нибудь с ним делать.