RTD3 job is failing due to libraries compatibility problem

https://jenkins.onap.org/job/rtdv3-global-verify-master/4686/console
14:23:36 docs run-test: commands[0] | sphinx-build -W -q -b html -n -d /w/workspace/rtdv3-global-verify-master/.tox/docs/tmp/doctrees ./docs/ /w/workspace/rtdv3-global-verify-master/docs/_build/html*14:23:37* 14:23:37 Exception occurred:14:23:37 File "/w/workspace/rtdv3-global-verify-master/.tox/docs-linkcheck/lib/python3.6/site-packages/blockdiag/parser.py", line 42, in <module>14:23:37 from funcparserlib.lexer import LexerError, Token, make_tokenizer*14:23:37* File "/w/workspace/rtdv3-global-verify-master/.tox/docs-linkcheck/lib/python3.6/site-packages/funcparserlib/lexer.py", line 80*14:23:37* def match_specs(specs, str, i, (line, pos)):