Add Calendar Specific Exception Classes

src/Objects/Calendar/Exceptions/NoCalendarEventInstancesException.php

@@ -0,0 +1,17 @@
+<?php
+/*
+ * Encore Digital Group - Planning Center PHP SDK
+ * Copyright (c) 2024. Encore Digital Group
+ */
+
+namespace EncoreDigitalGroup\PlanningCenter\Objects\Calendar\Exceptions;
+
+use Exception;
+
+class NoCalendarEventInstancesException extends Exception
+{
+    public function __construct()
+    {
+        parent::__construct('Calendar Event Has No Event Instances');
+    }
+}