code: def update(gems, ruby=None, runas=None, gem_bin=None):
      '''
      Update one or several gems.
  
      :param gems: string
          The gems to update.
      :param gem_bin: string : None
          Full path to ``gem`` binary to use.
      :param ruby: string : None
          If RVM or rbenv are installed, the ruby version and gemset to use.
          Ignored if ``gem_bin`` is specified.
      :param runas: string : None
          The user to run gem as.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' gem.update vagrant
      '''
      try:
          gems = gems.split()
      except AttributeError:
          pass
  
      return _gem(['update'] + gems,
                  ruby,
                  gem_bin=gem_bin,
                  runas=runasf update(gems, ruby=None, runas=None, gem_bin=None):
      '''
      Update one or several gems.
  
      :param gems: string
          The gems to update.
      :param gem_bin: string : None
          Full path to ``gem`` binary to use.
      :param ruby: string : None
          If RVM or rbenv are installed, the ruby version and gemset to use.
          Ignored if ``gem_bin`` is specified.
      :param runas: string : None
          The user to run gem as.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' gem.update vagrant
      '''
      try:
          gems = gems.split()
      except AttributeError:
          pass
  
      return _gem(['update'] + gems,
                  ruby,
                  gem_bin=gem_bin,
                  runas=runas)
docs: Update one or several gems.
  
      :param gems: string
          The gems to update.
      :param gem_bin: string : None
          Full path to ``gem`` binary to use.
      :param ruby: string : None
          If RVM or rbenv are installed, the ruby version and gemset to use.
          Ignored if ``gem_bin`` is specified.
      :param runas: string : None
          The user to run gem as.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' gem.update vagrant