Returns the ARN user or role whose credentials are used to call the API.
        Returns:
            (str): The ARN user or role

def get_caller_identity_arn(self):
        """Returns the ARN user or role whose credentials are used to call the API.
        Returns:
            (str): The ARN user or role
        """
        assumed_role = self.boto_session.client('sts').get_caller_identity()['Arn']

        if 'AmazonSageMaker-ExecutionRole' in assumed_role:
            role = re.sub(r'^(.+)sts::(\d+):assumed-role/(.+?)/.*$', r'\1iam::\2:role/service-role/\3', assumed_role)
            return role

        role = re.sub(r'^(.+)sts::(\d+):assumed-role/(.+?)/.*$', r'\1iam::\2:role/\3', assumed_role)

        # Call IAM to get the role's path
        role_name = role[role.rfind('/') + 1:]
        try:
            role = self.boto_session.client('iam').get_role(RoleName=role_name)['Role']['Arn']
        except ClientError:
            LOGGER.warning("Couldn't call 'get_role' to get Role ARN from role name {} to get Role path."
                           .format(role_name))

        return role