public void Add(TKey1 key, SafeDictionary <TKey2, TValue> value)
 {
     this.internalDictionary.Add(key, value);
 }
 bool IDictionary <TKey1, SafeDictionary <TKey2, TValue> > .TryGetValue(TKey1 key, out SafeDictionary <TKey2, TValue> value)
 {
     return(this.internalDictionary.TryGetValue(key, out value));
 }