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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 alternative_initvalue(self) -> Union[bool, int, float]: """A user-defined value to be used instead of the value of class constant `INIT`. See the main documentation on class |SolverParameter| for more information. """

        if self._alternative_initvalue is None:
            raise AttributeError(
                f'No alternative initial value for solver parameter '
                f'{objecttools.elementphrase(self)} has been defined so far.')
        else:
            return self._alternative_initvalue