import tensorflow as tf

            'image_size': dataset.image_size,
            'K': dataset.classes,
            'norm_mean': norm_mean,
            'norm_std': norm_std
        }

        return (images, classes, train_params)

    def _build_model(self, **knobs):
        use_dynamic_arch = knobs['downscale']

        # Create graph
        graph = tf.Graph()

        with graph.as_default():
            # Define input placeholders to graph
            ph = self._make_placeholders()

            # Use fixed archs if specified, otherwise use placeholders'
            (normal_arch, reduction_arch) = self._get_fixed_cell_archs(**knobs)
            normal_arch = normal_arch if not use_dynamic_arch else ph.normal_arch
            reduction_arch = reduction_arch if not use_dynamic_arch else ph.reduction_arch

            # Initialize steps variable
