code: public byte[] flatten() {
          Node normRoot = normalize(node, expression);
          StringBuilder builder = new StringBuilder(expression.length);
          stringify(normRoot, expression, builder);
          return builder.toString().getBytes(Constants.UTF8);
      }
docs: Generates a byte[] that represents a normalized, but logically equivalent, form of this evaluator's expression.
  
  @return normalized expression in byte[] form