You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: timestamp.pb.go
    path of file: ./repos/plik/vendor/google.golang.org/protobuf/types/known/timestamppb
    
    the code of the file until where you have to start completion: // Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, ar
    
func (x *Timestamp) CheckValid() error {
	switch x.check() {
	case invalidNil:
		return protoimpl.X.NewError("invalid nil Timestamp")
	case invalidUnderflow:
		return protoimpl.X.NewError("timestamp (%v) before 0001-01-01", x)
	case invalidOverflow:
		return protoimpl.X.NewError("timestamp (%v) after 9999-12-31", x)
	case invalidNanos:
		return protoimpl.X.NewError("timestamp (%v) has out-of-range nanos", x)
	default:
		return nil
	}
}