old_contents: # AWS_ACCESS_KEY_ID - AWS access key.
  # AWS_SECRET_ACCESS_KEY - AWS secret key. Access and secret key variables override credentials stored in credential and config files.
  # AWS_DEFAULT_REGION - AWS region. This variable overrides the default region of the in-use profile, if set.
  #
  # env AWS_ACCESS_KEY_ID=AKIAJOVZ2DVGJKZAOJSQ \
  #     AWS_SECRET_ACCESS_KEY=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 \
  #     AWS_DEFAULT_REGION=ap-southeast-2 \
  #     python test_iam_credentials_envar.py
  import boto3
  s3 = boto3.resource('s3')
  for bucket in s3.buckets.all():
      print(bucket.name)
  
new_contents: # AWS_ACCESS_KEY_ID - AWS access key.
  # AWS_SECRET_ACCESS_KEY - AWS secret key. Access and secret key variables override credentials stored in credential and config files.
  # AWS_DEFAULT_REGION - AWS region. This variable overrides the default region of the in-use profile, if set.
  #
  # env AWS_ACCESS_KEY_ID=acb \
  #     AWS_SECRET_ACCESS_KEY=xyz \
  #     AWS_DEFAULT_REGION=ap-southeast-2 \
  #     python test_iam_credentials_envar.py
  import boto3
  s3 = boto3.resource('s3')
  for bucket in s3.buckets.all():
      print(bucket.name)
  
subject: Remove AWS credential (IAM user have already been deleted from AWS)