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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 get_closest(self, lon, lat, depth=0):
 """ Get the closest object to the given longitude and latitude and its distance. :param lon: longitude in degrees :param lat: latitude in degrees :param depth: depth in km (default 0) :returns: (object, distance) """

        xyz = spherical_to_cartesian(lon, lat, depth)
        min_dist, idx = self.kdtree.query(xyz)
        return self.objects[idx], min_dist