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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 flip_constraint(self, twig=None, solve_for=None, **kwargs):
 """ Flip an existing constraint to solve for a different parameter :parameter str twig: twig to filter the constraint :parameter solve_for: twig or actual parameter object of the new parameter which this constraint should constraint (solve for). :type solve_for: str or :class:`phoebe.parameters.parameters.Parameter :parameter **kwargs: any other tags to do the filter (except twig or context) """

        self._kwargs_checks(kwargs, additional_allowed_keys=['check_nan'])

        kwargs['twig'] = twig
        redo_kwargs = deepcopy(kwargs)
        undo_kwargs = deepcopy(kwargs)

        changed_params = self.run_delayed_constraints()

        param = self.get_constraint(**kwargs)

        if kwargs.pop('check_nan', True) and np.any(np.isnan([p.get_value() for p in param.vars.to_list()])):
            raise ValueError("cannot flip constraint while the value of {} is nan".format([p.twig for p in param.vars.to_list() if np.isnan(p.get_value())]))

        if solve_for is None:
            return param
        if isinstance(solve_for, Parameter):
            solve_for = solve_for.uniquetwig

        redo_kwargs['solve_for'] = solve_for
        undo_kwargs['solve_for'] = param.constrained_parameter.uniquetwig

        logger.info("flipping constraint '{}' to solve for '{}'".format(param.uniquetwig, solve_for))
        param.flip_for(solve_for)

        result = self.run_constraint(uniqueid=param.uniqueid, skip_kwargs_checks=True)

        self._add_history(redo_func='flip_constraint',
                          redo_kwargs=redo_kwargs,
                          undo_func='flip_constraint',
                          undo_kwargs=undo_kwargs)

        return param