about set_editor_property question, thanks

I have a landscape grass type asset, and I want to change the assets property, one named light_channels`s channel0,but when I through the war to get_editor_property ,then I can get the property value, but when I through the way set_editor_property("",xxx),I can not set the property value, then How can I do to set the property value, thanks.

oh, I used python language.