...
tracks_array = { "PART DRUMS" : 999,
                 "PART GUITAR" : 999,
                 "PART BASS" : 999,
                 "PART VOCALS" : 999,
                 "PART KEYS" : 999,
                 "PART REAL_KEYS_X": 999,
                 "PART REAL_KEYS_H": 999,
                 "PART REAL_KEYS_M": 999,
                 "PART REAL_KEYS_E": 999,
                 "PART KEYS_ANIM_LH": 999,
                 "PART KEYS_ANIM_RH": 999,
                 "HARM1": 999,
                 "HARM2": 999,
                 "HARM3": 999,
                 "EVENTS": 999,
                 "BEAT": 999,
                 "PART DRUMS 2X": 999,
                 "VENUE": 999,
                 "PART RHYTHM": 999,
                 "PART REAL_GUITAR": 999,
                 "PART REAL_GUITAR_22": 999,
                 "PART REAL_BASS": 999,
                 "PART REAL_BASS_22": 999
                 }
array_instruments = {
        "Drums" : "PART DRUMS",
        "2x Drums" : "PART DRUMS 2X",
        "Rhythm" : "PART RHYTHM",
        "Guitar" : "PART GUITAR",
        "Bass" : "PART BASS",
        "Keys" : "PART KEYS",
        "Pro Keys" : "PART REAL_KEYS",
        "Vocals" : "PART VOCALS",
        "Harmony 1" : "HARM1",
        "Harmony 2" : "HARM2",
        "Harmony 3" : "HARM3",
        "Pro Guitar" : "PART REAL_GUITAR",
        "Pro Guitar 22" : "PART REAL_GUITAR_22",
        "Pro Bass" : "PART REAL_BASS",
        "Pro Bass 22" : "PART REAL_BASS_22"
        }
array_dropdownid = { "PART DRUMS" : 0,
                     "PART GUITAR" : 1,
                     "PART BASS" : 2,
                     "PART KEYS" : 3,
                     "PART REAL_KEYS_X": 4,
                     "PART REAL_KEYS_H": 4,
                     "PART REAL _KEYS_H": 4,
                     "PART REAL_KEYS_M": 4,
                     "PART REAL_KEYS_E": 4,
                     "PART DRUMS 2X": 5,
                     "PART RHYTHM": 6,
                     "PART VOCALS": 7,
                     "PART REAL_GUITAR": 8,
                     "PART REAL_GUITAR_22": 8,
                     "PART REAL_BASS": 9,
                     "PART REAL_BASS_22": 9
                 }
...
def prep_tracks():
    global maxlen
    global tracks_array
    num_mi = RPR_CountMediaItems(0)

    for i in range(0, num_mi):
        mi = RPR_GetMediaItem(0,i)
        trackID = RPR_GetMediaItem_Track(mi)
        trackname = RPR_GetSetMediaTrackInfo_String(trackID, "P_NAME", "", 0)[3]
        chunk = ""
        instrument = ""
        (boolvar, mi, chunk, maxlen) = RPR_GetSetItemState(mi, chunk, maxlen)
        #CYCLING THROUGH ALL TRACKS TO FIND THOSE RELEVANT
        #This check needs to go off everytime a command is issued because if the user changes position of the tracks the IDs change
        if "PART BASS" == trackname:
            tracks_array["PART BASS"] = i
        elif "PART DRUMS 2X" == trackname or "PART DRUMS 2x" == trackname or "PART DRUMS_2x" == trackname or "PART DRUMS_2X" == trackname:
            tracks_array["PART DRUMS 2X"] = i
        elif "PART DRUMS" == trackname:
            tracks_array["PART DRUMS"] = i
        elif "PART GUITAR" == trackname:
            tracks_array["PART GUITAR"] = i
        elif "PART VOCALS" == trackname:
            tracks_array["PART VOCALS"] = i
        elif "PART KEYS" == trackname:
            tracks_array["PART KEYS"] = i
        elif "KEYS_X" in trackname:
            tracks_array["PART REAL_KEYS_X"] = i
        elif "KEYS_H" in trackname:
            tracks_array["PART REAL_KEYS_H"] = i
        elif "KEYS_M" in trackname:
            tracks_array["PART REAL_KEYS_M"] = i
        elif "KEYS_E" in trackname:
            tracks_array["PART REAL_KEYS_E"] = i
        elif "PART KEYS_ANIM_RH" == trackname:
            tracks_array["PART KEYS_ANIM_RH"] = i
        elif "PART KEYS_ANIM_LH" == trackname:
            tracks_array["PART KEYS_ANIM_LH"] = i
        elif "HARM1" == trackname:
            tracks_array["HARM1"] = i
        elif "HARM2" == trackname:
            tracks_array["HARM2"] = i
        elif "HARM3" == trackname:
            tracks_array["HARM3"] = i
        elif "EVENTS" == trackname:
            tracks_array["EVENTS"] = i
        elif "BEAT" == trackname:
            tracks_array["BEAT"] = i
        elif "VENUE" == trackname:
            tracks_array["VENUE"] = i
        elif "PART REAL_GUITAR" == trackname:
            tracks_array["PART REAL_GUITAR"] = i
        elif "PART REAL_GUITAR_22" == trackname:
            tracks_array["PART REAL_GUITAR_22"] = i
        elif "PART REAL_BASS" == trackname:
            tracks_array["PART REAL_BASS"] = i
        elif "PART REAL_BASS_22" == trackname:
            tracks_array["PART REAL_BASS_22"] = i
        else:
            instrument = "???"
    #PM("\ntracks_array:\n")
    #PM(tracks_array)
...
def pg_root_notes(instrument, estringlow, astring, dstring, gstring, bstring, estringhigh):

    #instrument (PART REAL_GUITAR, PART REAL_GUITAR_22, PART REAL_BASS, PART REAL_BASS_22)
    #all strings : tuning

    global maxlen

    instrument_track = tracks_array[instrument]
    notes_dict = notesname_array[notesname_instruments_array[instrument]]

    array_instrument_data = process_instrument(instrument_track)
    array_instrument_notes = array_instrument_data[1]
    end_part = array_instrument_data[2]
    start_part = array_instrument_data[3]
    array_notesevents = create_notes_array(array_instrument_notes)
    array_notes = array_notesevents[0]
    array_events = array_notesevents[1]
    notes_found = 0
    result = 0

    string1 = 0 + estringlow
    string2 = 0 + astring
    string3 = 0 + dstring
    string4 = 0 + gstring
    string5 = 0 + bstring
    string6 = 0 + estringhigh

    for x in range(0, len(array_notes)):
        note = array_notes[x]
        if notes_dict[note[2]][1] == "root_notes":
            notes_found = 1
            result = RPR_MB( "Root notes found. Do you want to delete them and proceed?", "Root notes found", 1 )
            break

    if result == 1 or notes_found == 0:
        array_temp = list(array_notes)
        array_notes = []
        for x in range(0, len(array_temp)):
            note = array_temp[x]
            if notes_dict[note[2]][1] != "root_notes":
                array_notes.append(note)
    else:
        return

    for x in range(0, len(array_notes)):
        note = array_notes[x]
        if notes_dict[note[2]][1] == "notes_x":
            #It's an expert note, let's add it as a root note
            pitch = note[2]
            velocity = int(str(note[3]), 16)
            new_note = list(note)
            openstring = 0
            if(pitch == 96):                    #Which string? Which note?
                openstring = 16 + string1
            elif(pitch == 97):
                openstring = 9 + string2
            elif(pitch == 98):
                openstring = 14 + string3
            elif(pitch == 99):
                openstring = 7 + string4
            elif(pitch == 100):
                openstring = 11 + string5
            elif(pitch == 101):
                openstring = 16 + string6
            root = openstring + velocity - 100
            roothigh = 15
            rootlow = 4
            while (root > roothigh):
                root = root - 12
                if(root < rootlow):
                    break
            while (root < rootlow):
                root = root + 12
                if(root > roothigh):
                    break
            new_note[2] = root
            array_notes.append(new_note)

    write_midi(instrument_track, [array_notes, array_events], end_part, start_part)