Create an IAM policy version using an Amazon SDK

def create_policy_version(policy_arn, actions, resource_arn, set_as_default):
    """
    Creates a policy version. Policies can have up to five versions. The default
    version is the one that is used for all resources that reference the policy.

    :param policy_arn: The ARN of the policy.
    :param actions: The actions to allow in the policy version.
    :param resource_arn: The ARN of the resource this policy version applies to.
    :param set_as_default: When True, this policy version is set as the default
                           version for the policy. Otherwise, the default
                           is not changed.
    :return: The newly created policy version.
    """
    policy_doc = {
        'Version': '2012-10-17',
        'Statement': [
            {
                'Effect': 'Allow',
                'Action': actions,
                'Resource': resource_arn
            }
        ]
    }
    try:
        policy = iam.Policy(policy_arn)
        policy_version = policy.create_version(
            PolicyDocument=json.dumps(policy_doc), SetAsDefault=set_as_default)
        logger.info(
            "Created policy version %s for policy %s.",
            policy_version.version_id, policy_version.arn)
    except ClientError:
        logger.exception("Couldn't create a policy version for %s.", policy_arn)
        raise
    else:
        return policy_version