How do I resolve the “Zencode runtime error” indicating an invalid ‘keyring’ when generating a public key using executeContract with Zenroom?

const generateKeys = async () => {
const contract = `
    Scenario 'ecdh': Generate a key
    Given I am 'c'
    When I create the ecdh key
    Then print my keyring
`;
try {
    const result = await executeContract(contract);
    console.log("Result in generateKeys:", result);

    // Extract the private key from the result
    const parsedResult = JSON.parse(result);
    const keyring = parsedResult.c.keyring;
    if (keyring && keyring.ecdh) {
        setPrivateKey(keyring.ecdh);
        return keyring.ecdh; 
    }
} catch (error) {
    console.error('Error generating keys:', error);
    throw error;         
}

};

const executeContract = async (contract, props = {}) => {
try {
    const result = await zencode_exec(contract, props);
    console.log('Contract execution result:', result);

    if (result && result.result) {
        return result.result;
    } else {
        throw new Error('Unexpected result format from zencode_exec');
    }
} catch (error) {
    console.error('Error executing contract:', error);
    throw error;
}

};

const contract = Rule check version 4.33.0 Scenario 'ecdh': Generate public key Given that I am known as 'c' Given that I have a valid 'keyring' When I create the ecdh public key Then print my 'ecdh public key';

const result = await executeContract(contract, { keys: privateKey });

How do I resolve the “Zencode runtime error” indicating an invalid ‘keyring’ when generating a public key using executeContract with Zenroom?