Swapped out print statements for proper logger logs

Preempting @guillermo-carrasco and @mariogiov by putting in proper logging instead of printing to stderr.
Another common way to do this is to skip using the index and show that you're only using one of the returned values by shunting the other one to a dummy variable:

```python
plot_basename, _ = os.path.splitext(os.path.basename(fname))
```