imported exception classes

Author: ugochimbo

src/Paystack.php

@@ -13,6 +13,8 @@
 
 use GuzzleHttp\Client;
 use Illuminate\Support\Facades\Config;
+use Unicodeveloper\Paystack\Exceptions\IsNullException;
+use Unicodeveloper\Paystack\Exceptions\PaymentVerificationFailedException;
 
 class Paystack {