text: //@ts-check
  let less = require('less');
  /* interface RenderOutput {
      css: string;
      map: string;
      imports: string[];
  } */
  function loader(source) {
      let callback = this.async();
      less.render(source, (err, output) => {
          console.log('output.css', output.css);
          callback(err, output.css);
      });
  }
  module.exports = loader;