<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def load_byte(buf, pos):
 """Load single byte"""

    end = pos + 1
    if end > len(buf):
        raise BadRarFile('cannot load byte')
    return S_BYTE.unpack_from(buf, pos)[0], end