woocommerce-paypal-payments/tests/stubs/WC_Payment_Gateway.php

<?php
declare( strict_types = 1 );

class WC_Payment_Gateway {

	public function get_option( string $key, $empty_value = null ) {
		return $key;
	}

	protected function init_settings() {

	}

	protected function get_return_url( $wcOrder ) {
		return $wcOrder;
	}

	public function process_admin_options() {

	}
}