Patricia, driving a motorcycle, was injured in a collision with an SUV driven by Debbie. Patricia sued Debbie in federal court under a negligence theory. Patricia's attorney hired an accident reconstruction expert. Dewey Billem, to examine skid marks, inspect vehicle and motorcycle damage, and determine the speed of the SUV and motorcycle at the time of the collision. Dewey Billem formed an opinion that Debbie did not stop at the appro- priate stop sign. Patricia plans to call Dewey Billem to testify at trial. How can Debbie's lawyer learn how Dewey Billem will testify?