Set an even-parity bit in a byte's MSB

Bytes sent over a noisy link often carry a parity bit so the receiver can detect a flipped bit. In this scheme the parity bit is the most significant bit (bit 7, value 128) and the code uses even parity: the full byte must contain an even number of 1 bits.

Implement:

def set_parity_bit(b: int) -> int: ...

• b is a byte, an integer in [0, 255]. Bits 0–6 are data; bit 7 may already hold anything.
• Return a byte whose bits 0–6 are unchanged and whose bit 7 is chosen so the total number of 1 bits is even.
• Change only the MSB. Use bit manipulation (masks, shifts, XOR), not string conversion.
• Raise ValueError if b is outside [0, 255].

Examples

In the second example the incoming MSB was 1, which would make the count odd, so it is cleared.

Be ready to extend the function to odd parity, to whole buffers of bytes, and to the receiver's check.

Reconstructed from the reported question; details may differ from what interviewers ask.