code: func (c *Client) GetWebSessionInfo(user string, sid string) (services.WebSession, error) {
  	out, err := c.Get(
  		c.Endpoint("users", user, "web", "sessions", sid), url.Values{})
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return services.GetWebSessionMarshaler().UnmarshalWebSession(out.Bytes())
  }
docs: // GetWebSessionInfo checks if a web sesion is valid, returns session id in case if
  // it is valid, or error otherwise.