You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: gem_filename.rb
    path of file: ./repos/rubocop/lib/rubocop/cop/bundler
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module RuboCop
  module Cop
    module Bundler
      # Verifi
    
        def register_gems_rb_offense(file_path, basename)
          message = case basename
                    when 'Gemfile'
                      MSG_GEMS_RB_REQUIRED
                    when 'Gemfile.lock'
                      MSG_GEMS_RB_MISMATCHED
                    end