/// <summary>
        /// Contains<br />
        /// 包含
        /// </summary>
        /// <param name="func">An instance of <see cref="IVariableHolidayFunc"/>.</param>
        /// <returns></returns>
        public bool Contains(IVariableHolidayFunc func)
        {
            if (func == null)
            {
                return(false);
            }

            if (_variableHolidayFuncs.Any(x => x.I18NIdentityCode == func.I18NIdentityCode))
            {
                return(true);
            }

//            if (_variableHolidayFuncs.Any(x => x.Name == func.Name && x.BelongsToCountry == func.BelongsToCountry))
//                return true;

            return(false);
        }
        /// <summary>
        /// Add
        /// </summary>
        /// <param name="func"></param>
        public void Add(IVariableHolidayFunc func)
        {
            if (func == null)
            {
                return;
            }
            var countryCode = func.BelongsToCountry.ToCode();

            if (_variableDailyNodes.TryGetValue(countryCode, out var node))
            {
                node.Add(func);
            }
            else
            {
                node = new VariableDailyNode(func.BelongsToCountry);
                node.Add(func);
                _variableDailyNodes.TryAdd(countryCode, node);
            }
        }
        /// <summary>
        /// Add
        /// </summary>
        /// <param name="func"></param>
        public void Add(IVariableHolidayFunc func)
        {
            if (func == null)
            {
                return;
            }

            if (func.BelongsToCountry != Country)
            {
                return;
            }

            if (Contains(func))
            {
                return;
            }

            _variableHolidayFuncs.Add(func);
        }
 /// <summary>
 /// Add <see cref="IVariableHolidayFunc"/> into <see cref="HolidayManager"/>.
 /// </summary>
 /// <param name="func"></param>
 public void Add(IVariableHolidayFunc func)
 {
     _variableDailyNodeTree.ExposeRoot.Add(func);
 }