Large prefix lists/sets on IOS-XR

Hi, What is the best/most efficient/most convenient way to push large prefix lists or sets to an XR router for BGP prefix filtering? Pushing thousands of lines through the CLI seems foolish, I tried using the load command but it seems horribly slow. What am I missing? :) Cheers! Sander --- for every complex problem, there’s a solution that is simple, neat, and wrong