Python: boto3 decrypt

Question

I'm trying to decrypt via the boto3 a ecrypted value with kms.

The value is encrypted via the aws cli and then stored:

aws kms encrypt --key-id xxx --plaintext "test"

The code that I'm trying to use to decrypt then is following:

    kms_response = kms.decrypt(
        CiphertextBlob = token
    )
    runner_token = kms_response['Plaintext']

The answer is unfortunately like this b'\cf6\pec-'. I'm tried to add following kms_response['Plaintext'].decode() to my script, but I get following error:

{
  "errorMessage": "'utf-8' codec can't decode byte 0xb1 in position 0: invalid start byte",
  "errorType": "UnicodeDecodeError",
  "stackTrace": [
    "  File \"/var/task/terminate_hook.py\", line 32, in lambda_handler\n    runner_token = kms_response['Plaintext'].decode()\n"
  ]
}

Has anyone an idea why this isn't working?

Thanks, Yannick