How to use the @loopback/core.DecoratorFactory.cloneDeep function in @loopback/core

for (const c in content) {
        debug('  processing response code %s with content-type %', code, c);
        processSchemaExtensions(spec, content[c].schema);
      }
    }

    debug('  processing parameters for method %s', op);
    let params = MetadataInspector.getAllParameterMetadata(
      OAI3Keys.PARAMETERS_KEY,
      constructor.prototype,
      op,
    );

    debug('  parameters for method %s: %j', op, params);
    if (params != null) {
      params = DecoratorFactory.cloneDeep(params);
      /**
       * If a controller method uses dependency injection, the parameters
       * might be sparse. For example,
       * ```ts
       * class MyController {
       *   greet(
       *     @inject('prefix') prefix: string,
       *     @param.query.string('name) name: string) {
       *      return `${prefix}`, ${name}`;
       *   }
       * ```
       */
      operationSpec.parameters = params
        .filter(p => p != null)
        .map(p => {
          // Per OpenAPI spec, `required` must be `true` for path parameters

constructor,
  );
  if (spec) {
    debug('  using class-level spec defined via @api()', spec);
    spec = DecoratorFactory.cloneDeep(spec);
  } else {
    spec = {paths: {}};
  }

  let endpoints =
    MetadataInspector.getAllMethodMetadata(
      OAI3Keys.METHODS_KEY,
      constructor.prototype,
    ) ?? {};

  endpoints = DecoratorFactory.cloneDeep(endpoints);
  for (const op in endpoints) {
    debug('  processing method %s', op);

    const endpoint = endpoints[op];
    const verb = endpoint.verb!;
    const path = endpoint.path!;

    let endpointName = '';
    /* istanbul ignore if */
    if (debug.enabled) {
      const className = constructor.name || '';
      const fullMethodName = `${className}.${op}`;
      endpointName = `${fullMethodName} (${verb} ${path})`;
    }

    const defaultResponse = {

function resolveControllerSpec(constructor: Function): ControllerSpec {
  debug(`Retrieving OpenAPI specification for controller ${constructor.name}`);

  let spec = MetadataInspector.getClassMetadata(
    OAI3Keys.CLASS_KEY,
    constructor,
  );
  if (spec) {
    debug('  using class-level spec defined via @api()', spec);
    spec = DecoratorFactory.cloneDeep(spec);
  } else {
    spec = {paths: {}};
  }

  let endpoints =
    MetadataInspector.getAllMethodMetadata(
      OAI3Keys.METHODS_KEY,
      constructor.prototype,
    ) ?? {};

  endpoints = DecoratorFactory.cloneDeep(endpoints);
  for (const op in endpoints) {
    debug('  processing method %s', op);

    const endpoint = endpoints[op];
    const verb = endpoint.verb!;