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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 _lens_light_internal(self, x_grid, y_grid, kwargs_lens_light, model_bool_list=None):
 """ evaluates only part of the light profiles :param x_grid: :param y_grid: :param kwargs_lens_light: :return: """

        if model_bool_list is None:
            model_bool_list = [True] * len(kwargs_lens_light)
        lens_light = np.zeros_like(x_grid)
        for i, bool in enumerate(model_bool_list):
            if bool is True:
                lens_light_i = self.LensLightModel.surface_brightness(x_grid, y_grid, kwargs_lens_light, k=i)
                lens_light += lens_light_i
        return lens_light