Int to Byte (big endian) State Machine, in Python, type annotated.

int_to_byte_state_machine.py

class StateMachine:
    def __init__(self, value: int) -> None:
        self.value: int = value
        self.state = "START"
        self.byte_list: list[int] = []

    def run(self) -> bytes:
        while self.state != "END":
            self.transition()
        return bytes(self.byte_list[::-1])

    def transition(self) -> None:
        if self.state == "START":
            if self.value == 0:
                self.state = "END"
            else:
                self.byte_list.append(self.value & 0xFF)
                self.value >>= 8
                self.state = "RUNNING"
        elif self.state == "RUNNING":
            if self.value == 0:
                self.state = "END"
            else:
                self.byte_list.append(self.value & 0xFF)
                self.value >>= 8


sm = StateMachine(1024)
byte_data: bytes = sm.run()
print(byte_data)