implement Maybe comparator
implement Maybe comparator

kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground