After quickly looking at the OpenFermion code, hokru is right. There isn’t enough information here to say whether this is a Psi4 error or an OpenFermion-Psi4 error. Give us the .out file. If you suspect a Psi4 error, always give us a Psi4 output file.
Until then, all I can say is that the molecule object never has an hf_energy attribute set, which may be due to molecule.load() in _run_psi4.py::run_psi4 failing for reasons unknown, or maybe some other reason.
This is the totality of the output from the script: https://pastebin.com/jC2FLhN1
There are no output files created in the directory where I run the script. Could someone try to see if they are able to run the script by installing OpenFermion and OpenFermion-Psi4? If not I think I’ll create a github issue in OpenFermion-Psi4. (Sorry I can’t post a link to OpenFermion’s github, the forum rules only allow me 2 links since I’m a new user.)