code: func (c *Client) GetValues(keys []string) (map[string]string, error) {
  	vars := make(map[string]string)
  	for _, key := range keys {
  		resp, err := c.client.Get(context.Background(), key, &client.GetOptions{
  			Recursive: true,
  			Sort:      true,
  			Quorum:    true,
  		})
  		if err != nil {
  			return vars, err
  		}
  		err = nodeWalk(resp.Node, vars)
  		if err != nil {
  			return vars, err
  		}
  	}
  	return vars, nil
  }
docs: // GetValues queries etcd for keys prefixed by prefix.