def _setoct(self, octstring):
        """Reset the bitstring to have the value given in octstring."""
        octstring = tidy_input_string(octstring)
        # remove any 0o if present
        octstring = octstring.replace('0o', '')
        binlist = []
        for i in octstring:
            try:
                if not 0 <= int(i) < 8:
                    raise ValueError
                binlist.append(OCT_TO_BITS[int(i)])
            except ValueError:
                raise CreationError("Invalid symbol '{0}' in oct initialiser.", i)
        self._setbin_unsafe(''.join(binlist))
Reset the bitstring to have the value given in octstring.