human
Solve the following python programming problem given the following code:
@ test.create_stubs ({ 
    api.neutron : ('network_list',), 
    quotas : ('tenant_quota_usages',), 
}) 
def test_subnet_create_button_shown_when_quota_disabled_index(self) : 
    network_id = self.networks.first ().id 
    def _find_subnet_button(res) : 
        return self.getAndAssertTableRowAction (res, 'networks', 'subnet', network_id) 
self._test_create_button_shown_when_quota_disabled (<MASK>) 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is a proper replacement for <MASK>.
def _find_subnet_button(