How to use the bitsharesjs.PublicKey.fromPublicKeyString function in bitsharesjs

getInputType(value) {
        // OK
        if (!value) return null;
        if (value[0] === "#" && utils.is_object_id("1.2." + value.substring(1)))
            return "id";
        if (ChainValidation.is_account_name(value, true)) return "name";
        if (this.props.allowPubKey && PublicKey.fromPublicKeyString(value))
            return "pubkey";
        return null;
    }

getInputType(value) {
        // OK
        if (!value) return null;
        if (value[0] === "#" && utils.is_object_id("1.2." + value.substring(1)))
            return "id";
        if (ChainValidation.is_account_name(value, true)) return "name";
        if (this.props.allowPubKey && PublicKey.fromPublicKeyString(value))
            return "pubkey";
        return null;
    }

isValidPubKey(value) {
        return !!PublicKey.fromPublicKeyString(value);
    }

getNameType(value) {
        if (!value) return null;
        if (value[0] === "#" && utils.is_object_id("1.2." + value.substring(1))) return "id";
        if (ChainValidation.is_account_name(value, true)) return "name";
        if (this.props.allowPubKey && PublicKey.fromPublicKeyString(value)) return "pubkey";
        return null;
    }

isValidPubKey(value) {
        return !!PublicKey.fromPublicKeyString(value);
    }

return new Promise(resolve => {
        let public_key = PublicKey.fromPublicKeyString(backup_pubkey);
        let onetime_private_key = key.get_random_key(entropy);
        let walletString = JSON.stringify(wallet_object, null, 0);
        compress(walletString, compression_mode, compressedWalletBytes => {
            let backup_buffer = Aes.encrypt_with_checksum(
                onetime_private_key,
                public_key,
                null /*nonce*/,
                compressedWalletBytes
            );

            let onetime_public_key = onetime_private_key.toPublicKey();
            let backup = Buffer.concat([
                onetime_public_key.toBuffer(),
                backup_buffer
            ]);
            resolve(backup);

function verify_text(text, signedHex, publicKey) {
    //检测内容是不是具有签名的人签名的
    var signed2 = Signature.fromHex(signedHex);
    var publicKey = PublicKey.fromPublicKeyString(publicKey);
    return signed2.verifyBuffer(text, publicKey);
}