public static String extractScript(Object obj) {
    if (obj instanceof String string) {
      var matcher = EXPRESSION_PATTERN.matcher(string);
      if (matcher.matches()) {
        return matcher.group(1);
      }
    }
    return null;
  }
Returns the script text between the {@code "${ ... }"} characters.
planetiler-custommap/src/main/java/com/onthegomap/planetiler/custommap/expression/ConfigExpressionScript.java