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: types.go
    path of file: ./repos/moby/vendor/github.com/zmap/zcrypto/x509/ct
    
    the code of the file until where you have to start completion: package ct

// This file contains selectively chosen snippets of
// github.com/google/certificate-transparency-go@ 5cfe585726ad9d990d4db524d6ce2567b13e2f80
//
// These snippets only perform deserializ
    
func (d *DigitallySigned) FromBase64String(b64 string) error {
	raw, err := base64.StdEncoding.DecodeString(b64)
	if err != nil {
		return fmt.Errorf("failed to unbase64 DigitallySigned: %v", err)
	}
	ds, err := UnmarshalDigitallySigned(bytes.NewReader(raw))
	if err != nil {
		return fmt.Errorf("failed to unmarshal DigitallySigned: %v", err)
	}
	*d = *ds
	return nil
}