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: vis.rb
    path of file: ./repos/homebrew-core/Formula/v
    
    the code of the file until where you have to start completion: class Vis < Fo
    
  def caveats
    on_macos do
      <<~EOS
        To avoid a name conflict with the macOS system utility /usr/bin/vis,
        this text editor must be invoked by calling `vise` ("vis-editor").
      EOS
    end
  end