Applies self.style_function to each feature of self.data.

def style_data(self):
        """Applies self.style_function to each feature of self.data."""

        def recursive_get(data, keys):
            if len(keys):
                return recursive_get(data.get(keys[0]), keys[1:])
            else:
                return data

        geometries = recursive_get(self.data, self.object_path.split('.'))['geometries']  # noqa
        for feature in geometries:
            feature.setdefault('properties', {}).setdefault('style', {}).update(self.style_function(feature))