请问栅格图如何做maskout？

vortexroc

我按照脚本的例子做contourfm类型的图可以正常输出，但是改为imshow类型就出错了，请问王老师怎么做栅格类型的maskout图形呢？

axesm()
m_myregion= shaperead(u'd:/temp/Data/aregion.shp')
geoshow(m_myregion, visible=False)
layer=imshow(ybdatas)
masklayer(m_myregion,[layer])
colorbar(layer)
show()
错误提示是：
Traceback (most recent call last):
  File "<iostream>", line 114, in <module>
  File "<iostream>", line 18, in output_pic
  File "D:\Program Files (x86)\MeteoInfo\pylib\mipylib\plotlib\miplot.py", line 5837, in masklayer
    layer.layer.setMaskout(True)
AttributeError: 'org.meteoinfo.legend.LegendScheme' object has no attribute 'layer'

MeteoInfo

imshowm