I have got a solution, but its a hack. Our mobile tests and desktop tests are in separate packages, and their page classes are also separate. This can be leveraged to decide to decide what kind of test we are running and what we expect.

We can put the following code snippet in `__init__` method of `browserid.pages.sign_in.SignIn` class:

```
        import inspect
        self.is_mobile = True if 'mobile' in inspect.stack()[1][1].split('/') else False
```

Finally, we can do something like this:
```
if self.is_mobile:
    self.selenium.find_element(*self._on_mobile_next_locator).click()
else:
    self.selenium.find_element(*self._on_desktop_next_locator).click() 
```

Verifying that this works for me.