code: func (r *Region) SwitchPeer(storeID uint64) bool {
  	for _, p := range r.meta.Peers {
  		if p.GetStoreId() == storeID {
  			r.peer = p
  			return true
  		}
  	}
  	return false
  }
docs: // SwitchPeer switches current peer to the one on specific store. It returns
  // false if no peer matches the storeID.