PNG IHDR Z sBIT|d pHYs a a?i 9tEXtSoftware matplotlib version 2.1.1, http://matplotlib.org/ O IDATxwT?қ (E(" ({/DhQUcM>i{$Ɔ=րaA JS:c1W|^9ms3{c1c1c1 X 1c1c13