Unreal 4 too long animation fade in and fade out effect (simple batch)

              I want to make a fade in and fade out effect, but I forgot how to do it. After searching for a long time, I finally found a simple batch of emm

direct operation

1. The entire level sequence (I just made this for a demo)

2. Select the fade track

3. Dot is over (0 is white, 1 is black)

 Then just according to your own needs, just make keyframes.