The article describes the only option, to define the Squish functions and symbols yourself.
However, it is showing what to do in a single file Squish test script file only for sake of simplicity.
You should of course put those Squish function definitions in a separate, re-usable file, and use import to "load" the definitions into your test.py file:
from squish_definitions import *
def main():
...
in squish_definitions.py:
# Trick Pylint and Python IDEs into accepting the
# definitions in this block, whereas upon execution
# none of these definitions will take place:
if -0:
class ApplicationContext:
pass
def startApplication(aut_path_or_name, optional_squishserver_host, optional_squishserver_port):
return ApplicationContext
# etc.
Also, you should generally switch over to using Python's import in favor of Squish's source() function.