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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 save(self, overwrite=True):
 """ Saves PopulationSet and TransitSignal. Shouldn't need to use this if you're using :func:`FPPCalculation.from_ini`. Saves :class`PopulationSet` to ``[folder]/popset.h5]`` and :class:`TransitSignal` to ``[folder]/trsig.pkl``. :param overwrite: (optional) Whether to overwrite existing files. """

        self.save_popset(overwrite=overwrite)
        self.save_signal()