% yes | python3 -c "import pty; pty.spawn(['cat'])"
y
...
y^CTraceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3.10/pty.py", line 181, in spawn
    _copy(master_fd, master_read, stdin_read)
  File "/usr/lib/python3.10/pty.py", line 161, in _copy
    _writen(master_fd, data)
  File "/usr/lib/python3.10/pty.py", line 127, in _writen
    n = os.write(fd, data)
KeyboardInterrupt