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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 dissolve(self, by=None, aggfunc=None):
 # type: (Optional[str], Optional[Callable]) -> FeatureCollection """Dissolve geometries and rasters within `groupby`. """

        if by:
            agg = partial(dissolve, aggfunc=aggfunc)  # type: Callable[[BaseCollection], GeoFeature]
            return self.groupby(by).agg(agg)

        else:
            return FeatureCollection([dissolve(self, aggfunc)])