Nix install of flask-admin fails

I’m very excited by this guide as my students often want to deploy their class projects. I’d like to give them a production-ready learning environment. I’m working around the lack of Flask-Security in Nix but I’d really like to include Flask-Admin. When I include pkgs.python39Packages.flask-admin in my replit.nix file, I get the following error:

nix error: building nix env: exit status 100
Output has been trimmed to the last 20 lines
flask_admin/model/__init__.py                   3      0   100%
flask_admin/model/ajax.py                      11      5    55%
flask_admin/model/base.py                     741    221    70%
flask_admin/model/filters.py                  127     65    49%
flask_admin/model/form.py                     100     70    30%
flask_admin/model/helpers.py                   14      5    64%
flask_admin/model/template.py                  71      6    92%
flask_admin/model/typefmt.py                   28      9    68%
flask_admin/model/widgets.py                  119    100    16%
flask_admin/tools.py                           55     18    67%
flask_admin/translations/__init__.py            0      0   100%
---------------------------------------------------------------
TOTAL                                        3078   1192    61%
----------------------------------------------------------------------
Ran 49 tests in 21.333s

FAILED (SKIP=3, errors=5)
builder for '/nix/store/1m83jizxksch8vq4k40sh9lzj00j4y2m-python3.9-flask-admin-1.5.6.drv' failed with exit code 1
error: build of '/nix/store/1m83jizxksch8vq4k40sh9lzj00j4y2m-python3.9-flask-admin-1.5.6.drv' failed

Do I need some sort of configuration file for this install? Thanks!