Bourbon Fundamentals - Tint and Shade Function

This topic is for the [Tint and Shade Function] exercise in the [Bourbon Fundamentals] trail. Post any questions, corrections, or pointers you have to share with other Upcase subscribers.
[Tint and Shade Function]: https://exercises.upcase.com/exercises/tint-and-shade-mixin
[Bourbon Fundamentals]: Bourbon Fundamentals | Online Tutorial by thoughtbot