def readTupleAndExtra(self, stream):
length, symbol = self.decodePeek(stream.peek(self.maxLength))<EOL>stream.pos += length<EOL>extraBits = self.extraBits(symbol.index)<EOL>return length, symbol, extraBits, stream.read(extraBits)<EOL>
Read symbol and extrabits from stream.
        Returns symbol length, symbol, extraBits, extra
        >>> olleke.pos = 6
        >>> MetablockLengthAlphabet().readTupleAndExtra(olleke)
        (2, Symbol(MLEN, 4), 16, 46)