python matplotlib 警告 MatplotlibDeprecationWarning: shading=‘flat‘ ... is deprecate

plt.pcolormesh(x1,x2,grid_hat,cmap=cm_light)

• 报警告

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.
plt.pcolormesh(x1,x2,grid_hat,cmap=cm_light)

• 原因
  shading默认值为‘flat’，3.3版本之后，当X,Y,C参数维度相同时反对使用’flat’
• 解决

plt.pcolormesh(x1,x2,grid_hat,shading='auto',cmap=cm_light)