M method
Implementation
MfuncTuple M(Uint8List candidbytes, CandidBytes_i start_i) {
int v = ByteData.sublistView(candidbytes, start_i, start_i+1).getInt8(0);
MfuncTuple m_func_tuple = MfuncTuple(Int8(v), start_i+1);
return m_func_tuple;
}