rails 5.2.4.1 gem is broken on ruby 2.2.x due to use of safe navigation operator
rails 5.2.4.1 gem is broken on ruby 2.2.x due to use of safe navigation operator

which is fixed via https://github.com/rails/rails/commit/892eab777c418135ce0646e91bc9ebb08a29ab9b

amatsuda/kawaii_validation