How to use the dialogflow.EntityTypesClient function in dialogflow

import * as dialogflow from "dialogflow";

const agentsClient = new dialogflow.AgentsClient();
const contextsClient = new dialogflow.ContextsClient();
const entityTypesClient = new dialogflow.EntityTypesClient();
const intentsClient = new dialogflow.IntentsClient();
const sessionEntityTypesClient = new dialogflow.SessionEntityTypesClient();
const sessionsClient = new dialogflow.SessionsClient();

// TODO: Add real significant tests

async function listEntityTypes(projectId) {
  // [START dialogflow_list_entity_types]
  // Imports the Dialogflow library
  const dialogflow = require('dialogflow');

  // Instantiates clients
  const entityTypesClient = new dialogflow.EntityTypesClient();

  // The path to the agent the entity types belong to.
  const agentPath = entityTypesClient.projectAgentPath(projectId);

  const request = {
    parent: agentPath,
  };

  // Call the client library to retrieve a list of all existing entity types.
  const [response] = await entityTypesClient.listEntityTypes(request);
  response.forEach(entityType => {
    console.log(`Entity type name: ${entityType.name}`);
    console.log(`Entity type display name: ${entityType.displayName}`);
    console.log(`Number of entities: ${entityType.entities.length}\n`);
  });
  return response;

async function listEntities(projectId, entityTypeId) {
  // [START dialogflow_create_entity]
  // Imports the Dialogflow library
  const dialogflow = require('dialogflow');

  // Instantiates clients
  const entityTypesClient = new dialogflow.EntityTypesClient();

  // The path to the agent the entity types belong to.
  const entityTypePath = entityTypesClient.entityTypePath(
    projectId,
    entityTypeId
  );

  // The request.
  const request = {
    name: entityTypePath,
  };

  // Call the client library to retrieve a list of all existing entity types.
  const [response] = await entityTypesClient.getEntityType(request);
  response.entities.forEach(entity => {
    console.log(`Entity value: ${entity.value}`);

async function deleteEntity(projectId, entityTypeId, entityValue) {
  // [START dialogflow_delete_entity]
  // Imports the Dialogflow library
  const dialogflow = require('dialogflow');

  // Instantiates clients
  const entityTypesClient = new dialogflow.EntityTypesClient();

  // The path to the agent the entity types belong to.
  const entityTypePath = entityTypesClient.entityTypePath(
    projectId,
    entityTypeId
  );

  const request = {
    parent: entityTypePath,
    entityValues: [entityValue],
  };

  // Call the client library to delete the entity type.
  await entityTypesClient.batchDeleteEntities(request);
  console.log(`Entity Value ${entityValue} deleted`);
  // [END dialogflow_delete_entity]

async function createEntityType(projectId, displayName, kind) {
  // [START dialogflow_create_entity_type]
  // Imports the Dialogflow library
  const dialogflow = require('dialogflow');

  // Instantiates clients
  const entityTypesClient = new dialogflow.EntityTypesClient();

  // The path to the agent the created entity type belongs to.
  const agentPath = entityTypesClient.projectAgentPath(projectId);

  const createEntityTypeRequest = {
    parent: agentPath,
    entityType: {
      displayName: displayName,
      kind: kind,
    },
  };

  const responses = await entityTypesClient.createEntityType(
    createEntityTypeRequest
  );
  console.log(`Created ${responses[0].name} entity type`);

async function deleteEntityType(projectId, entityTypeId) {
  // [START dialogflow_delete_entity_type]
  // Imports the Dialogflow library
  const dialogflow = require('dialogflow');

  // Instantiates clients
  const entityTypesClient = new dialogflow.EntityTypesClient();

  const entityTypePath = entityTypesClient.entityTypePath(
    projectId,
    entityTypeId
  );

  const request = {
    name: entityTypePath,
  };

  // Call the client library to delete the entity type.
  const response = await entityTypesClient.deleteEntityType(request);
  console.log(`Entity type ${entityTypePath} deleted`);
  return response;
  // [END dialogflow_delete_entity_type]
}

async function createEntity(projectId, entityTypeId, entityValue, synonyms) {
  // [START dialogflow_create_entity]
  // Imports the Dialogflow library
  const dialogflow = require('dialogflow');

  // Instantiates clients
  const entityTypesClient = new dialogflow.EntityTypesClient();

  // The path to the agent the created entity belongs to.
  const agentPath = entityTypesClient.entityTypePath(projectId, entityTypeId);

  const entity = {
    value: entityValue,
    synonyms: synonyms,
  };

  const createEntitiesRequest = {
    parent: agentPath,
    entities: [entity],
  };

  const [response] = await entityTypesClient.batchCreateEntities(
    createEntitiesRequest