```ruby
class Cocktail < Cask
  version :latest
  sha256 :no_check

  url 'http://usa.maintain.se/CocktailYE.dmg'
  appcast 'http://www.maintain.se/downloads/sparkle/yosemite/yosemite.xml'
  homepage 'http://maintain.se/cocktail'
  license :unknown

  app 'Cocktail.app'

  # todo replace this with a conditional
  caveats <<-EOS.undent
    This version of Cocktail is for OS X Yosemite only. If you are using other versions of
    OS X, please run 'brew tap caskroom/versions' and install cocktail-mountainlion /
    cocktail-lion / cocktail-snowleopard / cocktail-mavericks
  EOS
end
```

Edit Cocktail cask in order to use conditionals
user
```ruby
class Cocktail < Cask
  version :latest
  sha256 :no_check

  if MacOS.version == :snow_leopard
    url 'http://usa.maintain.se/CocktailSLE.dmg'
    appcast 'http://www.maintain.se/downloads/sparkle/snowleopard/snowleopard.xml'
  elsif MacOS.version == :lion
    url 'http://usa.maintain.se/CocktailLionEdition.dmg'
    appcast 'http://www.maintain.se/downloads/sparkle/lion/lion.xml'
  elsif MacOS.version == :mountain_lion
    url 'http://usa.maintain.se/CocktailMLE.dmg'
    appcast 'http://www.maintain.se/downloads/sparkle/mountainlion/mountainlion.xml'
  elsif MacOS.version == :mavericks
    url 'http://usa.maintain.se/CocktailME.dmg'
    appcast 'http://www.maintain.se/downloads/sparkle/mavericks/mavericks.xml'
  else
    url 'http://usa.maintain.se/CocktailYE.dmg'
    appcast 'http://www.maintain.se/downloads/sparkle/yosemite/yosemite.xml'
  end

  homepage 'http://www.maintain.se/cocktail'
  license :unknown

  app 'Cocktail.app'
end
```
assistant