How to use the braintree-web.setup function in braintree-web

cvv: {
                    selector: '#braintree-credit-card-cvv'
                },
                expirationDate: {
                    selector: '#braintree-credit-card-expiration-date'
                }
            };
        }

        if ($('.braintree-paypal-method').length) {
            braintreeSetupSettings.paypal = {
                container: 'braintree-paypal-container'
            };
        }

        braintree.setup(braintreeClientToken, 'custom', braintreeSetupSettings);
    }