docs: def installed(name, default=False, user=None):
      '''
      Verify that the specified ruby is installed with rbenv. Rbenv is
      installed if necessary.
  
      name
          The version of ruby to install
  
      default : False
          Whether to make this ruby the default.
  
      user: None
          The user to run rbenv as.
  
          .. versionadded:: 0.17.0
  
      .. versionadded:: 0.16.0
      '''
      ret = {'name': name, 'result': None, 'comment': '', 'changes': {}}
      rbenv_installed_ret = copy.deepcopy(ret)
  
      if name.startswith('ruby-'):
          name = re.sub(r'^ruby-', '', name)
  
      if __opts__['test']:
          ret = _ruby_installed(ret, name, user=user)
          if not ret['result']:
              ret['comment'] = 'Ruby {0} is set to be installed'.format(name)
          else:
              ret['comment'] = 'Ruby {0} is already installed'.format(name)
          return ret
  
      rbenv_installed_ret = _check_and_install_rbenv(rbenv_installed_ret, user)
      if rbenv_installed_ret['result'] is False:
          ret['result'] = False
          ret['comment'] = 'Rbenv failed to install'
          return ret
      else:
          return _check_and_install_ruby(ret, name, default, user=user)