Fix warning about precedence issues

This is a new warning in Perl 5.20, and it really spotted a bug.

Issue: https://rt.cpan.org/Public/Bug/Display.html?id=99019
Fix documentation
Do not return empty lists explicitly

Returning an empty list explicitly "return ()" is usually an error. This
commit fixes two such places.
Refactoring
v1.0.1

  [Fixes]

  - (RT-99019) Fix warning about precedence issues.