Button color contrast function

Hi!

I would like to customize the function that is responsible for applying the text color on the buttons.

// MDB Mixins
// Set the color of the button and badge    
@function set-notification-text-color($color) {
      @if (lightness($color) > 80) {
        @return $black-base; // Lighter backgorund, return dark color
      }
      @else {
        @return $white-base; // Darker background, return light color
      }
    }

The contrast ratio set in the function does not pass the WebAIM test. Text still shows up white on a yellow background. I would like to know if there is a way to customize that function to fit my needs. I tried copying the function to the _custom-styles.scss file but it does not work. I am not looking for a hard-coded css override (but I'll do that if there's no other way).

I don't know how the function handles the contrast ratio but if I drop it to > 50 it seems to do the trick.