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: guardian_set.go
    path of file: ./repos/wormhole/wormchain/x/wormhole/types
    
    the code of the file until where you have to start completion: package types

import (
	bytes "bytes"
	"fmt"

	"github.com/ethereum/go-ether
    
func (gs GuardianSet) ValidateBasic() error {
	for i, key := range gs.Keys {
		if len(key) != 20 {
			return fmt.Errorf("key [%d]: len %d != 20", i, len(key))
		}
	}

	if len(gs.Keys) == 0 {
		return fmt.Errorf("guardian set must not be empty")
	}

	if len(gs.Keys) > 255 {
		return fmt.Errorf("guardian set length must be <= 255, is %d", len(gs.Keys))
	}

	return nil
}