How to use the node-opcua-secure-channel.SecurityPolicy.Basic128Rsa15 function in node-opcua-secure-channel

assert(endpoint instanceof EndpointDescription);
    const endpoint_securityPolicy = fromURI(endpoint.securityPolicyUri);
    if (endpointUrl && endpoint.endpointUrl! !== endpointUrl) {
        return false;
    }
    return (endpoint.securityMode === securityMode && endpoint_securityPolicy === securityPolicy);
}

const defaultSecurityModes = [
    MessageSecurityMode.None,
    MessageSecurityMode.Sign,
    MessageSecurityMode.SignAndEncrypt
];
const defaultSecurityPolicies = [
    SecurityPolicy.Basic128Rsa15,
    SecurityPolicy.Basic256,
// xx UNUSED!!    SecurityPolicy.Basic256Rsa15,
    SecurityPolicy.Basic256Sha256
];

assert(endpoint instanceof EndpointDescription);
    const endpoint_securityPolicy = fromURI(endpoint.securityPolicyUri);
    if (endpointUrl && endpoint.endpointUrl! !== endpointUrl) {
        return false;
    }
    return (endpoint.securityMode === securityMode && endpoint_securityPolicy === securityPolicy);
}

const defaultSecurityModes = [
    MessageSecurityMode.None,
    MessageSecurityMode.Sign,
    MessageSecurityMode.SignAndEncrypt
];
const defaultSecurityPolicies = [
    SecurityPolicy.Basic128Rsa15,
    SecurityPolicy.Basic256,
// xx UNUSED!!    SecurityPolicy.Basic256Rsa15,
    SecurityPolicy.Basic256Sha256
];

userIdentityTokens.push({
            policyId: "certificate_basic256",
            tokenType: UserTokenType.UserName,

            issuedTokenType: null,
            issuerEndpointUrl: null,
            securityPolicyUri: SecurityPolicy.Basic256
        });

        userIdentityTokens.push({
            policyId: "certificate_basic128",
            tokenType: UserTokenType.UserName,

            issuedTokenType: null,
            issuerEndpointUrl: null,
            securityPolicyUri: SecurityPolicy.Basic128Rsa15
        });

        userIdentityTokens.push({
            policyId: "certificate_basic256Sha256",
            tokenType: UserTokenType.UserName,

            issuedTokenType: null,
            issuerEndpointUrl: null,
            securityPolicyUri: SecurityPolicy.Basic256Sha256
        });

        userIdentityTokens.push({
            policyId: "certificate_basic256Sha256",
            tokenType: UserTokenType.Certificate,

            issuedTokenType: null,

function securityPolicyLevel(securityPolicy: UAString): number {
    switch (securityPolicy) {
        case SecurityPolicy.None:
            return 0;
        case SecurityPolicy.Basic128:
            return 0;
        case SecurityPolicy.Basic128Rsa15:
            return 0;
        case SecurityPolicy.Basic192:
            return 1;
        case SecurityPolicy.Basic192Rsa15:
            return 2;
        case SecurityPolicy.Basic256:
            return 3;
        case SecurityPolicy.Basic256Rsa15:
            return 3;
        case SecurityPolicy.Basic256Sha256:
            return 3;
        default:
            return 0;
    }
}

userIdentityTokens.push({
            policyId: "certificate_basic256",
            tokenType: UserTokenType.UserName,

            issuedTokenType: null,
            issuerEndpointUrl: null,
            securityPolicyUri: SecurityPolicy.Basic256
        });

        userIdentityTokens.push({
            policyId: "certificate_basic128",
            tokenType: UserTokenType.UserName,

            issuedTokenType: null,
            issuerEndpointUrl: null,
            securityPolicyUri: SecurityPolicy.Basic128Rsa15
        });

        userIdentityTokens.push({
            policyId: "certificate_basic256Sha256",
            tokenType: UserTokenType.UserName,

            issuedTokenType: null,
            issuerEndpointUrl: null,
            securityPolicyUri: SecurityPolicy.Basic256Sha256
        });

        userIdentityTokens.push({
            policyId: "certificate_basic256Sha256",
            tokenType: UserTokenType.Certificate,

            issuedTokenType: null,

function securityPolicyLevel(securityPolicy) {
    switch (securityPolicy) {
        case SecurityPolicy.None:
            return 0;
        case SecurityPolicy.Basic128:
            return 0;
        case SecurityPolicy.Basic128Rsa15:
            return 0;
        case SecurityPolicy.Basic192:
            return 1;
        case SecurityPolicy.Basic192Rsa15:
            return 2;
        case SecurityPolicy.Basic256:
            return 3;
        case SecurityPolicy.Basic256Rsa15:
            return 3;
        case SecurityPolicy.Basic256Sha256:
            return 3;
        default:
            return 0;
    }
}