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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _unpack_bytes(bytes):

 """
 Unpack a set of bytes into an integer. First pads to 4 bytes.
 Little endian.
 """

    if bytes == b'':
        return 0
    int_length = 4
    len_diff = int_length - len(bytes)
    bytes = bytes + len_diff * b'\x00'
    return struct.unpack("<L", bytes)[0]