Children’s Health Insurance Program under title XXI of such Act ( 42 U.S.C. 1397aa et seq. )). Such guidance shall include technical assistance and best practices regarding each of the following: (1) Recommended legal mechanisms for activating coverage of services furnished by advanced psychology trainees under such programs. (2) Recommended billing codes and code modifiers for services furnished by advanced psychology trainees. (3) Examples of States that have used waivers under the Medicaid program or Children's Health Insurance Program to enable coverage of services furnished by advanced psychology trainees under such programs.