How to require custom sass functions

[qiu8310]

I know require a custom sass functions with sass CLI:

sass main.scss main.css -r ./custom_func.rb

and with compass CLI:

compass compile -r ./custom_func.rb

But I don't know how to config to require my custom sass function with this grunt plugin?

_About sass custom function: official docs_

[qiu8310]

I used require config, but it don't work!

compass: {
    options: {
        require: [
            './app/lib/custom_func.rb',
            'ceaser-easing'
        ]
    }
}

ceaser-easing is a public gem package, and it can work, but my custom_func.rb just don't work!

[qiu8310]

OMG, It works today, I didn't change anything !?