matplotlib 3D绘图警告；MatplotlibDeprecationWarning: Axes3D(fig) adding itself to the figure is deprecate

警告内容：

MatplotlibDeprecationWarning: Axes3D(fig) adding itself to the figure is deprecated since 3.4. Pass the keyword argument auto_add_to_figure=False and use fig.add_axes(ax) to suppress this warning. The default value of auto_add_to_figure will change to False in mpl3.5 and True values will no longer work in 3.6. This is consistent with other Axes classes.
ax = Axes3D(fig)

解决方法：
按照提示在Axes3D的参数中加上auto_add_to_figure=False

ax = Axes3D(fig,auto_add_to_figure=False)

后面再加上：

fig.add_axes(ax)

再运行就不会有警告了。