As @AlbSan had to tell, there is a conflict between test.py, line 31, and epaper2in9.py line 148.
test.py submits a byte string as argument to clear_frame_memory, which is there packed into a list, which then is top be converted to a bytearray. That is not possible. So either, the call in test.py should submit just a single integer (0xff instead of b'\xff'), or the repackaging in epaper2in9.py should be omitted. @AlbSan went for the first choice.
P.S.: I wonder how the test code could have worked for you.
As @AlbSan had to tell, there is a conflict between test.py, line 31, and epaper2in9.py line 148. test.py submits a byte string as argument to clear_frame_memory, which is there packed into a list, which then is top be converted to a bytearray. That is not possible. So either, the call in test.py should submit just a single integer (0xff instead of b'\xff'), or the repackaging in epaper2in9.py should be omitted. @AlbSan went for the first choice.
P.S.: I wonder how the test code could have worked for you.