def span(self, index):
lower = self.value0+sum(<NUM_LIT:1><<x for x in self.extraTable[:index])<EOL>upper = lower+(<NUM_LIT:1><<self.extraTable[index])<EOL>return lower, upper-<NUM_LIT:1><EOL>
Give the range of possible values in a tuple
        Useful for mnemonic and explanation