def int_to_bytes(i: int, b_len: int) -> bytes:
    """
    Convert an non-negative int to big-endian unsigned bytes.
    :param i: The non-negative int.
    :param b_len: The length of bytes converted into.
    :return: The bytes.
    """
    return i.to_bytes(length=b_len, byteorder='big', signed=False)