AppMetrics.AccessKeys.IsAllowed C# (CSharp) Method

        static bool IsAllowed(string key)
        {
            lock (Sync)
            {
                if (_keys == null)
                {
                    _keys = AppSettings.Instance.AccessKeys;
                }
                var keyIsPresent = _keys.Contains(key);
                return keyIsPresent;
            }
        }