Antisymmetrized Product of Strongly Orthogonal Geminal (APSG) method

To get a deeper understanding of electronic structure methods, like Hartree-Fock, MP2, and Coupled Cluster method, there are many small programs (codes) available in Python, C++ or Fortran, for example, [Daniel Crawford's website](http://sirius.chem.vt.edu/wiki/doku.php?id=crawdad:programming), [Joshua website](https://joshuagoings.com/)


Does any one know any implementation of a simple Antisymmetrized Product of Strongly-orthogonal Geminals (APSG) method [(Geminal Model Chemistry)](https://doi.org/10.1063/1.1503773) for, say, two geminals (LiH, or H4, etc.) in Python or another programing language? 


I will be grateful if someone can share this type of code (implementation) to get a better understanding of geminal based methods.


