You should make this step more abstract. Try following code:
```python
BUTTONS = {
    'CC': '.hide-subtitles',
    'volume': '.volume',
}
@step('Hover over "([^"]*)" button$')
def hover_over_button(_step, button):
    button = button.strip();
    if button in BUTTONS.keys():
        world.browser.find_by_css(BUTTONS[button]).mouse_over()

```