Make sure evolver is on the system path. This is as simple as running
ln -s /Absolute/path/to/evolver /usr/local/bin/evolver
import evolver
with evolver.Evolver('/path/to/evolver') as E:
E.run_command('foo := 3')
output = E.run_command('print foo')
print(output) # prints the string 3
Get pip. Clone the repository and run
pip install --editable /path/to/repo
To download the surface evolver, see its homepage.