How to remove container outline

hi i need remove container outline
this my code

 cont = lv_cont_create(bg_middle, NULL);
    lv_obj_set_auto_realign(cont, true);                    /*Auto realign when the size changes*/
    lv_obj_align_origo(cont, NULL, LV_ALIGN_CENTER, 0, 0);  /*This parametrs will be sued when realigned*/
    lv_cont_set_fit(cont, LV_FIT_TIGHT);
    lv_cont_set_layout(cont, LV_LAYOUT_COLUMN_MID); 
    lv_obj_set_style_local_bg_color(cont, LV_OBJ_PART_MAIN, 
     lv_obj_set_size(cont, 150, 150);

Look at the outline and border style properties. The simplest is to set width to 0.

can you give me example code , and modify my code?