Dinosaurus model - W1A2: RNN or LSTM?

I noticed a comment in the model function of the Dinosaurus lab (W1A2) mentions Initialize the hidden state of your LSTM. The optimize function we implement in the lab is an RNN model not an LSTM so this comment seems incorrect?

The reason I am asking is that section 1.2 of the the music generation lab (W1A3) mentions that the LSTM model we are using is similar to Dinosaurus, but implemented in Keras. This confused me because Dinosaurus is an RNN and music generation is a LSTM.

The LSTM is one type of RNN.

When I read LSTM I start thinking of memory cell and gates which an RNN doesn’t have, but they are all in the same family so I see the point now. Thanks.