Gradient fill animation

[justaskingforafriend]

How can I animate gradient fill of an arrow to make it look like this? I was able to do it in another app, but can't find it in After Effects. The idea is to swap colors in gradient in a few keyframes, thus making them moving.
Blue-Cyan-Green, then Green-Blue-Cyan, then Cyan-Green-Blue
Thank you!

[justaskingforafriend]

Solved.