While studying [Pandas Style](http://pandas.pydata.org/pandas-docs/stable/style.html), I got to the following:

```
def highlight_max(s):
    '''
    highlight the maximum in a Series yellow.
    '''
    is_max = s == s.max()
    return ['background-color: yellow' if v else '' for v in is_max]

```

How should I read `is_max = s == s.max()`?