public static function get_customer_tokens( $customer_id, $gateway_id = '' ) {
		if ( $customer_id < 1 ) {
			return array();
		}

		$tokens = self::get_tokens(
			array(
				'user_id'    => $customer_id,
				'gateway_id' => $gateway_id,
			)
		);

		return apply_filters( 'woocommerce_get_customer_payment_tokens', $tokens, $customer_id, $gateway_id );
	}