Hi David,
you can just install the experimental version for python 3.7 (which is stable in the core features)
pip install python-libsbml-experimental
Just checked in a virtualenv and works fine in python3.7.
Best Matthias
(test-py37-libsbml) mkoenig@prime1:~$ python
Python 3.7.3 (default, Mar 26 2019, 01:59:45)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import libsbml
>>> print(libsbml.__version__)
5.17.2