I can't check ga_instance.run_completed == False during runtime because ga_instance.run_completed is initialized to True only after a finished run. It was never initialized to False inside of class GA. This line is missing from pygad.py I suppose (lines 911 - 941):

self.run_completed = False

Workaround for now in example.py:

ga_instance = pygad.GA(
  # [...]
)

ga_instance.run_completed = False