Sets current s value to the last accepted value

def reject(self):
        """Sets current s value to the last accepted value"""
        self.stochastic.revert()

        # Increment rejected count
        self.rejected[self.current_kernel] += 1

        if self.verbose > 1:
            print_(
                self._id,
                "rejected, reverting to value =",
                self.stochastic.value)