import tensorflow as tf


        v_path = conv3d(rb, 3, channel_nr, 'SYMMETRIC', 'relu')
        v_path = conv3d(v_path, 3, 1, 'SYMMETRIC', None)

        w_path = conv3d(rb, 3, channel_nr, 'SYMMETRIC', 'relu')
        w_path = conv3d(w_path, 3, 1, 'SYMMETRIC', None)
        

        b_out = tf.keras.layers.concatenate([u_path, v_path, w_path])

        return b_out

def upsample3d(input_tensor, res_increase):
    """
        Resize the image by linearly interpolating the input
        using TF '``'resize_bilinear' function.
