Custom helper functions are not calling after upgrading from 2 to3

created custom helper and added async function as below:

async fillField(selector, value) {
await this.puppeteer.fillField(element, value)
await this.puppeteer.page.keyboard.press("Tab")
// function to wait for ajax Load
}

Calling fillField in test files

I.fillField(selector, value) --> Its calling `await this.puppeteer.fillField(element, value)` instead of custom helper function