Need for specific turtle object in SpiroAnimator.__init__

[rwkopcke]

EDIT: despite these error flags in PyCharm, the program does run.

at
https://github.com/electronut/pp/blob/master/spirograph/spiro.py

in lines 116, 117, and 127
the PyCharm (Python 3.8.1) flags the methods turtle.window_width(), turtle.window_height(), and turtle.ontimer(...) with an unresolved reference error.