LGTM.com - false positive: py/procedure-return-value-used

I'm not sure how the analyzer is even _finding_ the function whose return value it insists is being used, from a test suite file that's not referenced in any way from the flagged code file.

Obviously this code uses the return value of *a* function. In fact, its return value _may_ be `None`. But there's no way to tell that it's _always_ `None`, because the function called is dynamically determined.

https://lgtm.com/projects/g/sopel-irc/sopel/snapshot/b921e6fe0662d3f24cb468c0008465b037682294/files/sopel/plugins/rules.py?sort=name&dir=ASC&mode=heatmap#x5dd3ccc00f1e0e0:1