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

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

  let endpoints =
    MetadataInspector.getAllMethodMetadata(
      OAI2Keys.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})`;
    }

    let operationSpec = endpoint.spec;

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

  let spec = MetadataInspector.getClassMetadata(
    OAI2Keys.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(
      OAI2Keys.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!;

op,
    );
    if (params == null) {
      params = MetadataInspector.getMethodMetadata(
        OAI2Keys.METHODS_WITH_PARAMETERS_KEY,
        constructor.prototype,
        op,
      );
    }
    debug('  parameters for method %s: %j', op, params);
    if (params != null) {
      const bodyParams = params.filter(p => p && p.in === 'body');
      if (bodyParams.length > 1) {
        throw new Error('More than one body parameters found: ' + bodyParams);
      }
      params = DecoratorFactory.cloneDeep(params);
      /**
       * If a controller method uses dependency injection, the parameters
       * might be sparsed. 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);
    }
    operationSpec['x-operation-name'] = op;