Error when typing shift T or shift B

[igoldsteinh]

Hi, really enjoying working on this project, thanks for sharing it.
I am working through the setup instructions for v2.2 waveshare. I can successfully run sudo python main.py and am able to type on the screen/navigate with arrow keys.
However, for some keys, it appears that using shift is causing an error (I have so far found it for shift + t and shift + b).
Here is the error message I get on my terminal:

Exception in thread Thread-7 (listen):
Traceback (most recent call last):
  File "/usr/lib/python3.11/threading.py", line 1038, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.11/threading.py", line 975, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/local/lib/python3.11/dist-packages/keyboard/__init__.py", line 294, in listen
    _os_keyboard.listen(self.direct_callback)
  File "/usr/local/lib/python3.11/dist-packages/keyboard/_nixkeyboard.py", line 141, in listen
    callback(KeyboardEvent(event_type=event_type, scan_code=scan_code, name=name, time=time, device=device_id, is_keypad=is_keypad, modifiers=pressed_modifiers_tuple))
  File "/usr/local/lib/python3.11/dist-packages/keyboard/__init__.py", line 236, in direct_callback
    if not all(hook(event) for hook in self.blocking_hooks):
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/keyboard/__init__.py", line 236, in <genexpr>
    if not all(hook(event) for hook in self.blocking_hooks):
               ^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/keyboard/__init__.py", line 474, in <lambda>
    return hook(lambda e: e.event_type == KEY_UP or callback(e), suppress=suppress)
                                                    ^^^^^^^^^^^
  File "/home/isaacgoldstein/zerowriter1/e-Paper/RaspberryPi_JetsonNano/python/examples/zerowriter.py", line 742, in handle_key_press
    self.input_content += char
TypeError: can only concatenate str (not "NoneType") to str

I am using the archived version of bookworm recommended in issue 26. In case it is helpful, here is the keyboard I am using.

Any ideas on resolving this would be much appreciated!

[igoldsteinh]

Just a brief update: tried using a different keyboard, also tried re-installing OS and keyboard package, unfortunately still running into the same error.