MatplotlibDeprecationWarning in plotting
plotting.py:2037: MatplotlibDeprecationWarning: shading='flat' when X and Y have the same dimensions as C is deprecated since 3.3. Either specify the corners of the quadrilaterals with X and Y, or pass shading='auto', 'nearest' or 'gouraud', or set rcParams['pcolor.shading']. This will become an error two minor releases later.
im = ax.pcolormesh(x_bins, y_bins, hist, norm=norm, rasterized=True)