Could not use the service - Error

[ghost]

Hi
I could not use the service. I got this error and I guess it is because of the python version.

  File "app.py", line 21, in <module>
    import discoursegraphs as dg
  File "/usr/lib/python2.7/site-packages/discoursegraphs/__init__.py", line 23, in <module>
    from discoursegraphs.readwrite import (
  File "/usr/lib/python2.7/site-packages/discoursegraphs/readwrite/__init__.py", line 20, in <module>
    from discoursegraphs.readwrite.freqt import docgraph2freqt, write_freqt
  File "/usr/lib/python2.7/site-packages/discoursegraphs/readwrite/freqt.py", line 14, in <module>
    from discoursegraphs.readwrite.tree import sorted_bfs_successors
  File "/usr/lib/python2.7/site-packages/discoursegraphs/readwrite/tree.py", line 13, in <module>
    from nltk.tree import Tree, ParentedTree
  File "/usr/lib/python2.7/site-packages/nltk/__init__.py", line 128, in <module>
    from nltk.collocations import *
  File "/usr/lib/python2.7/site-packages/nltk/collocations.py", line 35, in <module>
    from nltk.probability import FreqDist
  File "/usr/lib/python2.7/site-packages/nltk/probability.py", line 333
    print("%*s" % (width, samples[i]), end=" ")

[ghost]

Resolved this issue by installing an old version of nltk
pip install nltk==3.0