Added isNullException

Author: Okubanjo Oluwafunsho

src/Exceptions/isNullException.php

@@ -0,0 +1,18 @@
+<?php
+
+/*
+ * This file is part of the Laravel Paystack package.
+ *
+ * (c) Prosper Otemuyiwa <prosperotemuyiwa@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Unicodeveloper\Paystack\Exceptions;
+
+use Exception;
+
+class isNullException extends Exception {
+
+}