按键上的Tkinter错误

Question

代码：

import tkinter
window = tkinter.Tk()
c = tkinter.Canvas(window, height=400, width=600, bg='green')
mid_x = 600 / 2
mid_y = 400 / 2
window.geometry("600x400")
window.title("window")

def ship_control(event):
    pass

c.bind_all('<KeyPress-a>', ship_control)
def start():
    global ship
    rock_speed = 10
    ship = c.create_oval(mid_x, mid_y, mid_x + 20, mid_y + 20, fill='red', outline='orange')

button_start = tkinter.Button(window, text='play', command=start)
button_start.pack()
c.pack()

错误：

>>> 
>>> Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Program Files\Python 3.5\lib\idlelib\run.py", line 121, in main
    seq, request = rpc.request_queue.get(block=True, timeout=0.05)
  File "C:\Program Files\Python 3.5\lib\queue.py", line 172, in get
    raise Empty
queue.Empty

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
ValueError: invalid literal for int() with base 10: '??'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files\Python 3.5\lib\tkinter\__init__.py", line 1534, in __call__
    args = self.subst(*args)
  File "C:\Program Files\Python 3.5\lib\tkinter\__init__.py", line 1252, in _substitute
    e.num = getint_event(b)
  File "C:\Program Files\Python 3.5\lib\tkinter\__init__.py", line 1231, in getint_event
    return int(s)
SystemError: result with error in PyObject_Call

如何重现：

打开程序，按播放然后按a。

我不知道有什么可能是错的，尽管我尝试在谷歌搜索。

我尝试添加打印但不会执行。

有谁知道我为什么会收到错误？

Answer 1

问题是我使用的是3.5而不是3.4。切换版本有效。