self.client = boto3.client('iam')
resources = self.client.list_roles().get('Roles')

for resource in resources:
    resource_arn = resource.get('Arn')
    gen_last_accessed = self.client.generate_service_last_accessed_details(Arn=resource_arn)

'IAM' object has no attribute 'generate_service_last_accessed_details'

- iam:GenerateServiceLastAccessedDetails
- iam:GetServiceLastAccessedDetails
- iam:ListRoles