def get_bytes(self, index, size):
pos = self.size() // <NUM_LIT:8> - <NUM_LIT:1> - index<EOL>return self[pos * <NUM_LIT:8> + <NUM_LIT:7> : (pos - size + <NUM_LIT:1>) * <NUM_LIT:8>]<EOL>
Extracts several bytes from a bitvector, where the index refers to the byte in a big-endian order

:param index: the byte index at which to start extracting
:param size: the number of bytes to extract
:return: A BV of size ``size * 8``