Preprocessing.py

notes = []

for file in glob.glob("midi_songs/*.mid"):
    midi = converter.parse(file) # Convert file into stream.Score Object
    
    print("parsing %s"%file)
    
    elements_to_parse = midi.flat.notes
    
    
    for ele in elements_to_parse:
        # If the element is a Note,  then store it's pitch
        if isinstance(ele, note.Note):
            notes.append(str(ele.pitch))

        # If the element is a Chord, split each note of chord and join them with +
        elif isinstance(ele, chord.Chord):
            notes.append("+".join(str(n) for n in ele.normalOrder))