Yeah, you could see it like that, but you could also see it the other way around... I will just rest my case with this dummy function:
```
def select_one_choice(conditions, choices):
    """Returns element from choice if condition is True, else 0"""
    res = []
    for cond, choice in zip(conditions, choices)
        res.append(cond if choices else 0)
    return res
```
This function is well defined, nothing special about it. Now you could add a check for 0-length, but there is no need and in numpy we don't, and the old function doesn't either.