键盘事件和event对象，请看看为什么会报错，该怎么改进

问题遇到的现象和发生背景

问题相关代码，请勿粘贴截图

# coding=utf-8

# 测试键盘和鼠标事件

from tkinter import *

root=Tk();root.geometry('500x300')

c1=Canvas(root,width=200,height=200,bg='green')
c1.pack()

def mouseTest (event):
    print('鼠标左键单击的位置（相对于父容器）：{0}，{1}'.format(event.x,event.y))
    print('鼠标左键单击的位置(相对于屏幕)：{0}，{1}'.format(event.x_root,event.y_root))
    print('事件绑定的组件：{0}'.format(event.widget))

def testDrag(event):
    c1.create_oval(event.x,event.y,event.x+1,event.y+1)


def keyboardTest(event):
    print('键的keycode:{0},键的插入：{1}，键的keysym：{2}'
          .format(event.keycode,event.char,event.keysym))

def press_a_test():
    print('press a')

def release_a_test():
    print('release a')

c1.bind('<Button-1>',mouseTest)
c1.bind('<B1-Motion>',testDrag)

root.bind('<KeyPress>',keyboardTest)
root.bind('<KeyPress-a>',press_a_test)
root.bind('<keyRelease-a>',release_a_test)

root.mainloop()

运行结果及报错内容

"C:\Program Files\python\python.exe" D:/pythonProject/gui/my14.py
Traceback (most recent call last):
  File "D:\pythonProject\gui\my14.py", line 36, in <module>
    root.bind('<keyRelease-a>',release_a_test)
  File "C:\Program Files\python\lib\tkinter\__init__.py", line 1421, in bind
    return self._bind(('bind', self._w), sequence, func, add)
  File "C:\Program Files\python\lib\tkinter\__init__.py", line 1375, in _bind
    self.tk.call(what + (sequence, cmd))
_tkinter.TclError: bad event type or keysym "keyRelease"

Process finished with exit code 1

我的解答思路和尝试过的方法

我想要达到的结果

第36行大小写的问题

root.bind('<KeyRelease-a>',release_a_test)