title: Make Sinatra Helpers available only in some routes (modular application)
body: <p>I have two different versions of an application that use slightly different versions of some methods.</p>
  
  <pre><code>module Sinatra
    class MyApp &lt; Sinatra::Base
      helpers Sinatra::Version1
      helpers Sinatra::Version2
    end
  end
  
  module Sinatra
    module Version1
      def say_hello
        puts "Hello from Version1"
      end
    end
    helpers Version1
  end
  
  module Sinatra
    module Version2
      def say_hello
        puts "Hello from Version2"
      end
    end
    helpers Version2
  end
  </code></pre>
  
  <p>I realize that helpers specified this way are "top level" and are made available to all routes.</p>
  
  <p>I would like to have the different versions of the methods available to different routes. Is there some way to accomplish this within a modular application?</p>