code: public final int getMaxArity() {
      Node params = getParametersNode();
      if (params != null) {
        Node lastParam = params.getLastChild();
        if (lastParam == null || !lastParam.isVarArgs()) {
          return params.getChildCount();
        }
      }
  
      return Integer.MAX_VALUE;
    }
docs: Gets the maximum number of arguments that this function requires, or Integer.MAX_VALUE if this
  is a variable argument function.