title: Python boto3 checking for valid bucket within region
body: <p>I have seen examples for checking whether an S3 bucket exists and have implemented them below. My bucket is located in us-east-1 region but the following code doesn't throw an exception. Is there a way to make the check region specific depending on my session?</p>
  <pre><code>session = boto3.Session(
      profile_name = 'TEST'
      ,region_name='ap-south-1'
  )
  
  s3 = session.resource('s3')
  
  bucket_name = 'TEST_BUCKET'
  
  try:
      s3.meta.client.head_bucket(Bucket = bucket_name)
  except ClientError as c:
      print(c)
  </code></pre>