add proper error messaging

Author: mufaddal-rohawala

src/sagemaker/session.py

@@ -654,7 +654,9 @@ def _bucket_owner_check(self, bucket_name):
             message = e.response["Error"]["Message"]
             if error_code == "403" and message == "Forbidden":
                 LOGGER.error(
-                    "Bucket %s exists, but not in the AWS account configured in AWS Session."
+                    "Since default_bucket param was not set, SageMaker Python SDK tried to use "
+                    "%s bucket. The bucket exists, but not in the AWS account configured in "
+                    "SageMaker Session."
                     "Please reach out to AWS Security to verify on bucket ownership."
                     "To unblock it's recommended to use custom default_bucket "
                     "param in sagemaker.Session",

tests/unit/test_default_bucket.py

@@ -85,7 +85,7 @@ def test_default_bucket_s3_needs_bucket_owner_access(sagemaker_session, datetime
         sagemaker_session.default_bucket()
 
     error_message = (
-        " exists, but not in the AWS account configured in AWS Session."
+        " exists, but not in the AWS account configured in SageMaker Session."
         "Please reach out to AWS Security to verify on bucket ownership."
         "To unblock it's recommended to use custom default_bucket "
         "param in sagemaker.Session"