def num_bytes_to_struct_char(n: int):
    """
    Given number of bytes, return the struct char that can hold those bytes.

    For example,
        2 = H
        4 = I
    """
    if n > 8:
        return None
    if n > 4:
        return "Q"
    if n > 2:
        return "I"
    if n > 1:
        return "H"
    if n == 1:
        return "B"
    return None