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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 _readsie(self, pos):
 """Return interpretation of next bits as a signed interleaved exponential-Golomb code. Advances position to after the read code. Raises ReadError if the end of the bitstring is encountered while reading the code. """

        codenum, pos = self._readuie(pos)
        if not codenum:
            return 0, pos
        try:
            if self[pos]:
                return -codenum, pos + 1
            else:
                return codenum, pos + 1
        except IndexError:
            raise ReadError("Read off end of bitstring trying to read code.")