update the documentation for creating s3 bucket to address the region mismatch issue.

docs/source/guide/s3-example-creating-buckets.rst

@@ -27,14 +27,22 @@ The name of an Amazon S3 bucket must be unique across all regions of the AWS
 platform. The bucket can be located in a specific region to minimize latency
 or to address regulatory requirements.
 
+.. note::
+    The ``LocationConstraint`` value is used to specify the region where a bucket
+    will be created. S3 requires ``LocationConstraint`` to be specified when creating
+    buckets using a client in regions other than ``us-east-1``. When no region is
+    specified, ``us-east-1`` is used by default. The example below ensures the S3
+    client is created in the same region as the bucket to avoid a
+    ``IllegalLocationConstraintException`` error.
+
 .. code-block:: python
 
     import logging
     import boto3
     from botocore.exceptions import ClientError
 
 
-    def create_bucket(bucket_name, region=None):
+    def create_bucket(bucket_name, region='us-east-1'):
         """Create an S3 bucket in a specified region
 
         If a region is not specified, the bucket is created in the S3 default
@@ -47,20 +55,17 @@ or to address regulatory requirements.
 
         # Create bucket
         try:
-            if region is None:
-                s3_client = boto3.client('s3')
-                s3_client.create_bucket(Bucket=bucket_name)
-            else:
-                s3_client = boto3.client('s3', region_name=region)
-                location = {'LocationConstraint': region}
-                s3_client.create_bucket(Bucket=bucket_name,
-                                        CreateBucketConfiguration=location)
+            bucket_config = {}
+            s3_client = boto3.client('s3', region_name=region)
+            if region != 'us-east-1':
+                bucket_config['CreateBucketConfiguration'] = {'LocationConstraint': region}
+
+            s3_client.create_bucket(Bucket=bucket_name, **bucket_config)
         except ClientError as e:
             logging.error(e)
             return False
         return True
 
-
 List existing buckets
 =====================
 
@@ -76,4 +81,3 @@ List all the existing buckets for the AWS account.
     print('Existing buckets:')
     for bucket in response['Buckets']:
         print(f'  {bucket["Name"]}')
-