hacks-guide-minimal-mistakes-theme/_sass/vendor/breakpoint/parsers/double/_double-string.scss

@function breakpoint-parse-double-string($first, $second) {
  $feature: '';
  $value: '';

  // Test to see which is the feature and which is the value
  @if (breakpoint-string-value($first) == true) {
    $feature: $first;
    $value: $second;
  }
  @else if (breakpoint-string-value($second) == true) {
    $feature: $second;
    $value: $first;
  }
  @else {
    @warn "Neither #{$first} nor #{$second} is a valid media query name.";
  }

  // Set Context
  $context-setter: private-breakpoint-set-context($feature, $value);

  @return '(#{$feature}: #{$value})';
}