docs: def _ruby_installed(ret, ruby, user=None):
      '''
      Check to see if given ruby is installed.
      '''
      default = __salt__['rbenv.default'](runas=user)
      for version in __salt__['rbenv.versions'](user):
          if version == ruby:
              ret['result'] = True
              ret['comment'] = 'Requested ruby exists'
              ret['default'] = default == ruby
              break
  
      return ret