add nova

nova/src/Exceptions/MissingActionHandlerException.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Laravel\Nova\Exceptions;
+
+use Exception;
+
+class MissingActionHandlerException extends Exception
+{
+    /**
+     * Create a new exception instance.
+     *
+     * @param  mixed  $action
+     * @param  string  $method
+     * @return static
+     */
+    public static function make($action, $method)
+    {
+        return new static('Action handler ['.get_class($action).'@'.$method.'] not defined.');
+    }
+}