Change Error handling in Blinky-Hello-World

[katoy]

I found wrong code in Blinky-Hello-World/register_thing.py

$ git diff fix_error_handling -- register_thing.py 
diff --git a/Blinky-Hello-World/register_thing.py b/Blinky-Hello-World/register_thing.py
index a7d9fec..6f8ce13 100644
--- a/Blinky-Hello-World/register_thing.py
+++ b/Blinky-Hello-World/register_thing.py
@@ -142,12 +142,11 @@ def generate_signer_certificate():
     print("Generating self-signed x.509 certificate...")
     try:
         aws_iot_reg_code = iot.get_registration_code()
-    except ClientError as e:
-        print(str(e))
-        print(e.response['Error']['Code'])
+    except ClientError:
+        print(ClientError.response['Error']['Code'])
         print("Error with the AWS CLI when running the command 'aws iot get-registration-code'.")
-        exit(1)
-
+        exit(0)
+    
     signer_public_key = signer_key.public_key()
     time_now = datetime.utcnow()
     days_to_expire = 365

When I used the modified code, I encountered the following error:

An error occurred (AccessDeniedException) when calling the GetRegistrationCode operation: User: arn:aws:iam::xxxxxxxxxxxx:user/xxx-xxx is not authorized to perform: iot:GetRegistrationCode on resource: * because no identity-based policy allows the iot:GetRegistrationCode action
AccessDeniedException