i ran this on repl.it after installing arsenal and crf package successfully.
Matplotlib created a temporary config/cache directory at /tmp/matplotlib-ykbg_s95 because the default path (/config/matplotlib) is not a writable directory; it is highly recommended to set the MPLCONFIGDIR environment variable to a writable directory, in particular to speed up the import of Matplotlib and to better support multiprocessing.
Traceback (most recent call last):
File "crf/example.py", line 160, in <module>
main()
File "crf/example.py", line 154, in main
run_test()
File "crf/example.py", line 126, in run_test
(L, A) = build_domain(train)
File "/home/runner/SorrowfulKnowledgeableOrigin/crf/crf/stringcrf.py", line 20, in build_domain
A.stop_growth()
AttributeError: 'Alphabet' object has no attribute 'stop_growth'```