i want to make my background image black gradient using css code example

Example: gradient image css

#show_bg_2 {
 
background-image:
  /*two color gradient over an image*/
linear-gradient(to bottom, rgba(245, 246, 252, 0.52), 
rgba(117, 19, 93, 0.73)),url('images/background.jpg');
 
width: 80%;
height: 400px;
background-size: cover;
}