impossible to exit from the file

[sylas]

Hi all ! This file works well, unless I try to exit. Look please at lines 17,18, 19. I am on Linux. Python 3.7.

import tty, sys, termios

class ReadChar():
    def __enter__(self):
        self.fd = sys.stdin.fileno()
        self.old_settings = termios.tcgetattr(self.fd)
        tty.setraw(sys.stdin.fileno())
        return sys.stdin.read(1)
    def __exit__(self, type, value, traceback):
        termios.tcsetattr(self.fd, termios.TCSADRAIN, self.old_settings)

def test():
    while True:
        with ReadChar() as rc:
            char = rc
        #if ord(char) == 3:
		#	sys.exit()   
        #elif ord(char) <= 32:
        if ord(char) <= 32:
            print("You entered character with ordinal {}."\
                        .format(ord(char)))
        else:
            print("You entered character '{}'."\
                        .format(char))
        #if char in "^C^D":
         #   sys.exit()

if __name__ == "__main__":
    test()

If I uncomment lines 17, 18, I have the following error:

Error:
sylvain@sylvain-HP-Laptop-15-bw0xx:~$ python get2.py
  File "get2.py", line 18
    sys.exit()   
                ^