How to write Gruntfile for Kraken Image Optimizer - gruntjs

Question

I can't figure out how to write the Gruntfile for Kraken Image Optimizer (not KrakenJs): https://github.com/kraken-io/kraken-node
For example, the Gruntfile for grunt-contrib-imagemin looks something like:
imagemin: { // Task
static: { // Target
options: { // Target options
optimizationLevel: 3,
//use: [mozjpeg()]
},
files: { // Dictionary of files
'dist/img.png': 'src/img.png', // 'destination': 'source'
'dist/img.jpg': 'src/img.jpg',
'dist/img.gif': 'src/img.gif'
}
},
dynamic: { // Another target
files: [{
expand: true, // Enable dynamic expansion
cwd: 'src/', // Src matches are relative to this path
src: ['**/*.{png,jpg,gif}'], // Actual patterns to match
dest: 'dist/' // Destination path prefix
}]
}
},
However the documentation for using Kraken on NodeJs looks like this:
var Kraken = require('kraken');
var kraken = new Kraken({
'api_key': 'your-api-key',
'api_secret': 'your-api-secret'
});
var params = {
file: '/path/to/image/file.jpg',
wait: true
};
kraken.upload(params, function(status) {
if (status.success) {
console.log('Success. Optimized image URL: %s', status.kraked_url);
} else {
console.log('Fail. Error message: %s', status.error);
}
});
// For advanced API usage simply alter the `params` object. For example:
var params = {
file: '/path/to/image/file.jpg',
wait: true,
resize: {
width: 100,
height: 75,
strategy: 'crop'
},
s3_store: {
key: 'AKIAO4AD5J4F1NA33Q12',
secret: 'AAwQwJSEgG9WpeCV20GlHI5hGKxKuw5qY80t4CCe',
bucket: 'assets',
path: 'images/layout/header.jpg'
},
webp: true,
lossy: true
};
How can I convert this to something that works in my Gruntfile?