How to use the policyuniverse.arn.ARN function in policyuniverse

"""Loads roles specified in file and calls _remove_permissions_from_role() for each one.

    Args:
        permissions (list)
        role_filename (string)
        commit (bool)

    Returns:
        None
    """
    roles = list()
    with open(role_filename, "r") as fd:
        roles = json.load(fd)

    for role_arn in tqdm(roles):
        arn = ARN(role_arn)
        if arn.error:
            LOGGER.error("INVALID ARN: {arn}".format(arn=role_arn))
            return

        account_number = arn.account_number
        role_name = arn.name.split("/")[-1]

        role_id = find_role_in_cache(dynamo_table, account_number, role_name)
        role = Role(get_role_data(dynamo_table, role_id))

        _remove_permissions_from_role(
            account_number,
            permissions,
            role,
            role_id,
            dynamo_table,

def inspect_entity_arn(self, entity, same, item):
        arn_input = entity.value
        if arn_input == '*':
            return set(['UNKNOWN'])

        arn = ARN(arn_input)
        if arn.error:
            self.record_arn_parse_issue(item, arn_input)

        if arn.tech == 's3':
            return self.inspect_entity_s3(entity, arn.name, same)

        return set([self.inspect_entity_account(entity, arn.account_number, same)])

def _arn_internet_accessible(self, arn_input):
        if '*' == arn_input:
            return True

        arn = ARN(arn_input)
        if arn.error:
            logger.warning('Auditor could not parse ARN {arn}.'.format(arn=arn_input))
            return '*' in arn_input

        if arn.tech == 's3':
            # S3 ARNs typically don't have account numbers.
            return False

        if not arn.account_number and not arn.service:
            logger.warning('Auditor could not parse Account Number from ARN {arn}.'.format(arn=arn_input))
            return True

        if arn.account_number == '*':
            return True

        return False

def check_unknown_cross_account(self, item):
        policies = self.load_resoruce_policies(item)
        for policy in policies:
            if policy.is_internet_accessible():
                continue
            for statement in policy.statements:
                if statement.effect != 'Allow':
                    continue
                for who in statement.whos_allowed():
                    if who.value == '*' and who.category == 'principal':
                        continue

                    # Ignore Service Principals
                    if who.category == 'principal':
                        arn = ARN(who.value)
                        if arn.service:
                            continue

                    entity = Entity.from_tuple(who)
                    if 'UNKNOWN' in self.inspect_entity(entity, item):
                        self.record_unknown_access(item, entity, list(statement.actions))

def check_root_cross_account(self, item):
        policies = self.load_resource_policies(item)
        for policy in policies:
            for statement in policy.statements:
                if statement.effect != 'Allow':
                    continue
                for who in statement.whos_allowed():
                    if who.category not in ['arn', 'principal']:
                        continue
                    if who.value == '*':
                        continue
                    arn = ARN(who.value)
                    entity = Entity.from_tuple(who)
                    if arn.root and self.inspect_entity(entity, item).intersection(set(['FRIENDLY', 'THIRDPARTY', 'UNKNOWN'])):
                        self.record_cross_account_root(item, entity, list(statement.actions))