Small notes program

main.py

notes = []

with open('Notes.txt', 'r') as f:
    for i, l in enumerate(f):
        l = l.strip()
        print(i, l)
        notes.append([l[:-4], l[-2] == 'X'])

while True:
    try:
        op = int(input('Mark as not finished: '))
    except ValueError:
        break
    notes[op][1] = False

while True:
    try:
        op = int(input('Mark as finished: '))
    except ValueError:
        break
    notes[op][1] = True

while True:
    op = input('Add more notes: ')
    if op == 'q' or op.isspace():
        break
    notes.append([op, False])

with open('Notes.txt', 'w') as f:
    for i in notes:
        output = i[0]
        if i[1]:
            output += ' [X]\n'
        else:
            output += ' [ ]\n'
        f.write(output)