You are reading an old version of the documentation (v2.0.0). For the latest version see https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.get_ygridlines.html
matplotlib

Travis-CI:

This Page

matplotlib.axes.Axes.get_ygridlines

Axes.get_ygridlines()

Get the y grid lines as a list of Line2D instances