private string getValueFromDict(ConcurrentDictionary<string, ConcurrentDictionary<string, string>> source, string keyValue, string subKeyValue)
{
  string result = null;
  ConcurrentDictionary<string, string> sourceValueObject;
  source.TryGetValue(keyValue, out sourceValueObject);
  sourceValueObject.TryGetValue(subKeyValue, out result);

  return result;
  }