I'm upgrading to Pants 2.16 and seeing something I wasn't expecting. Surely I'm missing something:

$ tree . -L 1
.
├── __filter.py
├── __nbconvert.py
├── notebook.pex
├── notebook.pex_bin_python_shim.sh
├── notebook.pex_pex_shim.sh
├── notebooks
├── __pycache__
├── __run.sh
└── __template.py.j2

3 directories, 6 files

In

./__run.sh

export PEX_MODULE=__nbconvert
cd /tmp/pants-sandbox-EuAiqL
./notebook.pex_pex_shim.sh nbconvert ...

Running it I get

$ ./__run.sh 
Traceback (most recent call last):
  File "/tmp/pants-sandbox-EuAiqL/.cache/pex_root/venvs/8af8dff5caba8ff4e3555dafecebf663b2d3b550/3ae15bb9525f8e6ffaefc76519921e604f1e7079/pex", line 274, in <module>
    runpy.run_module(module_name, run_name="__main__", alter_sys=True)
  File "/home/josh/.cache/pants/named_caches/pyenv/44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a/versions/3.8.16/lib/python3.8/runpy.py", line 203, in run_module
    mod_name, mod_spec, code = _get_module_details(mod_name)
  File "/home/josh/.cache/pants/named_caches/pyenv/44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a/versions/3.8.16/lib/python3.8/runpy.py", line 138, in _get_module_details
    raise error("No module named %s" % mod_name)
ImportError: No module named __nbconvert

So the only change I would expect to make a difference is PEX version?