human
Solve the following python programming problem given the following code:
def test_get_stack_versions(monkeypatch) : 
    cf = MagicMock () 
    elb = MagicMock () 
    def my_boto3(service, * args) : 
        if (service == 'cloudformation') : 
            return cf 
else : 
            if (service == 'elb') : 
                return elb 
else : 
                return MagicMock (side_effect = SyntaxError ('unknown option')) 
monkeypatch.setattr ('senza.traffic.get_stacks', MagicMock (return_value = [])) 
    monkeypatch.setattr ('boto3.client', my_boto3) 
    monkeypatch.setattr ('boto3.resource', my_boto3) 
    stack_version = list (get_stack_versions ('my-stack', 'my-region')) 
    assert (stack_version == []) 
    stack = MagicMock (stack_name = 'my-stack-1') 
    resource = [MagicMock (resource_type = 'AWS::ElasticLoadBalancing::LoadBalancer'), MagicMock (resource_type = 'AWS::Route53::RecordSet', physical_resource_id = 'myapp.example.org')] 
    cf.Stack.return_value = MagicMock (tags = [{ 
        'Value' : '1', 
        'Key' : 'StackVersion', 
}], notification_arns = ['some-arn'], resource_summaries = MagicMock (all = MagicMock (return_value = resource))) 
    elb.describe_load_balancers.return_value = { 
        'LoadBalancerDescriptions' : [{ 
            'DNSName' : 'elb-dns-name', 
}], 
} 
    monkeypatch.setattr ('senza.traffic.get_stacks', MagicMock (return_value = [SenzaStackSummary (cf), SenzaStackSummary ({ 
        'StackStatus' : 'ROLLBACK_COMPLETE', 
        'StackName' : 'my-stack-1', 
})])) 
    stack_version = list (get_stack_versions ('my-stack', 'my-region')) 
    assert (stack_version == [StackVersion ('my-stack', '1', ['myapp.example.org'], ['elb-dns-name'], ['some-arn'])]) 

    
    

    Fix the buggy line: monkeypatch.setattr ('senza.traffic.get_stacks', MagicMock (return_value = [SenzaStackSummary (cf), SenzaStackSummary ({
assistant
#Here is Python code to fix the buggy line: monkeypatch.

monkeypatch.setattr ('senza.traffic.get_stacks', MagicMock (return_value = [SenzaStackSummary (stack), SenzaStackSummary ({