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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def handle(cls, value, **kwargs):
 """Decrypt the specified value with a master key in KMS. kmssimple field types should be in the following format: [<region>@]<base64 encrypted value> Note: The region is optional, and defaults to the environment's `AWS_DEFAULT_REGION` if not specified. For example: # We use the aws cli to get the encrypted value for the string # "PASSWORD" using the master key called "myStackerKey" in # us-east-1 $ aws --region us-east-1 kms encrypt --key-id alias/myStackerKey \ --plaintext "PASSWORD" --output text --query CiphertextBlob # In stacker we would reference the encrypted value like: You can optionally store the encrypted value in a file, ie: kms_value.txt and reference it within stacker (NOTE: the path should be relative to the stacker config file):
 conf_key: ${kms file://kms_value.txt} # Both of the above would resolve to conf_key: PASSWORD """

        value = read_value_from_path(value)

        region = None
        if "@" in value:
            region, value = value.split("@", 1)

        kms = get_session(region).client('kms')

        # encode str value as an utf-8 bytestring for use with codecs.decode.
        value = value.encode('utf-8')

        # get raw but still encrypted value from base64 version.
        decoded = codecs.decode(value, 'base64')

        # decrypt and return the plain text raw value.
        return kms.decrypt(CiphertextBlob=decoded)["Plaintext"]