code: @Override
      public String visit(final JmesPathFunction function,
                          final Void aVoid) throws InvalidTypeException {
          final String prefix = "new " + function.getClass()
                  .getSimpleName() + "( ";
          return function.getExpressions().stream()
                  .map(a -> a.accept(this, aVoid))
                  .collect(Collectors.joining(",", prefix, ")"));
      }
docs: Generates the code for a new JmesPathFunction.
  
  @param function JmesPath function type
  @param aVoid    void
  @return String that represents a call to
  the new function expression
  @throws InvalidTypeException