Convert triplet of [label_store, symbol, description] into bytes
    for defining custom labels in the annotation file

def custom_triplet_bytes(custom_triplet):
    """
    Convert triplet of [label_store, symbol, description] into bytes
    for defining custom labels in the annotation file
    """
    # Structure: 0, NOTE, len(aux_note), aux_note, codenumber, space, codesymbol, space, description, (0 null if necessary)
    # Remember, aux_note string includes 'number(s)<space><symbol><space><description>''
    annbytes = [0, 88, len(custom_triplet[2]) + 3 + len(str(custom_triplet[0])), 252] + [ord(c) for c in str(custom_triplet[0])] \
               + [32] + [ord(custom_triplet[1])] + [32] + [ord(c) for c in custom_triplet[2]]

    if len(annbytes) % 2:
        annbytes.append(0)

    return annbytes