How to share a similar method between two models?

example.md

# The `title` methods in each model are so similar it feels like they should be able to be shared. 
# Normally this would be a good excuse to use a Concern, but is that even possible?

class Message < ApplicationRecord
  def title
    subject
  end
end

class Comment < ApplicationRecord
  def title
    subject.truncate(20)
  end
end