code: public static FunctionLib combineFLDs(FunctionLib[] flds) {
  	FunctionLib fl = new FunctionLib();
  	if (ArrayUtil.isEmpty(flds)) return fl;
  
  	setAttributes(flds[0], fl);
  
  	// add functions
  	for (int i = 0; i < flds.length; i++) {
  	    copyFunctions(flds[i], fl);
  	}
  	return fl;
      }
docs: return one FunctionLib contain content of all given Function Libs
  
  @param flds
  @return combined function lib