> The documentation says "The size of the image that is passed in is taken to specify the amount of padding, and so the `pad_factor` keyword should be equal to 1, i.e., no padding."

Given this, would it make more sense to have this line be 
```
if pad_factor != 1. and pad_factor != 0.:
```
In other words, make the default pad_factor when specifying a pad_image be 1, rather than 0 (or 4).