TypeError: ord() expected string of length 1, but int found

[archenroot]

On large input file with words to train I get(the input csv file is actually just pure 1 column list):

zangetsu@venus: pts/11: 16 files 192Kb -> ./generate_compressor_model.py ~/tmp/csv-compress-string/my_events.csv -o shoco_model.h 
finding bigrams ... done.
Traceback (most recent call last):
  File "./generate_compressor_model.py", line 391, in <module>
    main()
  File "./generate_compressor_model.py", line 305, in main
    max_chr = ord(max(successors.keys())) + 1
TypeError: ord() expected string of length 1, but int found

[archenroot]

Python 3 related...

[charmander]

See #18