I'm an expert in music, novice at coding, but I've studied enough python to be able to have written a code that uses a dictionary of dictionaries to return the song's interval numbers based on it's (musical) key. I studied the python library from MIT's music department called Music21, and used it to parse a midi or musicxml file to get the pitch value and the rhythm values of start time and duration for each note. I don't use many functions from them after the basic parse we just use a dictionary of dictionaries to return the data we choose. But we can use it to change the color of note heads, and print our desired data as lyrics under notes on a music staff in musescore app (free). I'm hoping to build a musescore plugin that my students can use to learn.
I need help re-creating the idea and going further, I'm looking for someone to troubleshoot problems I can't solve on my own and to help me plan my next coding steps.