Assignment 3 (Week 1): Jazz Improvisation with LSTM

I downloaded all the data and implemented this assignment on Google Colab, I saw: total # of unique values: 78. Whereas, I ran it on Coursera jupyter notebook, total # of unique values: 90. What was wrong with Google Colab? Please help me fix this problem (attached in the image below)

Sorry, I have not worked with Colab, and don’t have any suggestions for this.