def model_fn(self, x, t):
        """
        Convert the model to the noise prediction model or the data prediction model.
        """
        if self.predict_x0:
            return self.data_prediction_fn(x, t)
        else:
            return self.noise_prediction_fn(x, t)

        Convert the model to the noise prediction model or the data prediction model.
        
ControlNet-v1-1-nightly/ldm/models/diffusion/dpm_solver/dpm_solver.py