/*
 * Replace occurrences of %s in $string by $elements
 * ---
 * @access private
 * ---
 * @since 1.2.0
 * ---
 * @param {string}  $string   - string to check
 * @param {arglist} $elements - strings to use for replacements in %s
 * ---
 * @return {string}
 */

@function _ss-str-printf($string, $elements...) {
  $breaker: '%s'; 
  $result: $string;

  @for $i from 1 through length($elements) {
    $index: str-index($result, $breaker);
    @if $index {
      $result: str-slice($result, 1, $index - 1) + stringify(nth($elements, $i)) + str-slice($result, $index + str-length($breaker));
    }
    @else {
      @return $result;
    }
  }

  @return $result;
}
/*
 * Replace occurrences of %s in $string by $elements
 * ---
 * @access private
 * ---
 * @since 1.2.0
 * ---
 * @param {string}  $string   - string to check
 * @param {arglist} $elements - strings to use for replacements in %s
 * ---
 * @return {string}
 */

@function _ss-str-printf($string, $elements...) {
  $breaker: '%s'; 
  $result: $string;

  @for $i from 1 through length($elements) {
    $index: str-index($result, $breaker);
    @if $index {
      $result: str-slice($result, 1, $index - 1) + _ss-stringify(nth($elements, $i)) + str-slice($result, $index + str-length($breaker));
    }
    @else {
      @return $result;
    }
  }

  @return $result;
}

Fix error when only using private functions
Fix error when only using private functions