We propose a new Perturbation Theory framework that can be used to help with the projective solution of the Schrödinger equation for arbitrary wavefunctions. This Flexible Ansatz for N-body Perturbation Theory (FANPT) is based on our previously proposed Flexible Ansatz for N-body Configuration Interaction (FANCI). We derive recursive FANPT expressions including arbitrary orders in the perturbation hierarchy. We show that the FANPT equations are well-behaved across a wide range of conditions, including static correlation-dominated configurations and highly non-linear wavefunctions. The code is based on the research paper [Flexible Ansatz for N-Body Perturbation Theory] (https://arxiv.org/abs/2310.03096#:~:text=This%20Flexible%20Ansatz%20for%20N,orders%20in%20the%20perturbation%20hierarchy.)

Steps to run FANPT calculations (in progress)