code: func (s *Registry) Get(store Store, name string) (session *Session, err error) {
  	if !isCookieNameValid(name) {
  		return nil, fmt.Errorf("sessions: invalid character in cookie name: %s", name)
  	}
  	if info, ok := s.sessions[name]; ok {
  		session, err = info.s, info.e
  	} else {
  		session, err = store.New(s.request, name)
  		session.name = name
  		s.sessions[name] = sessionInfo{s: session, e: err}
  	}
  	session.store = store
  	return
  }
docs: // Get registers and returns a session for the given name and session store.
  //
  // It returns a new session if there are no sessions registered for the name.