Converts Bulma CSS framework from SASS to SCSS

bulmatoscss_gulpfile.js

// Bulma to scss gulp script
// In your terminal
// 1. npm install -D sass-convert gulp bulma gulp-sass gulp-replace
// 2. gem install sass

var gulp = require("gulp"),
    replace = require('gulp-replace'),
    converter = require('sass-convert'),
    sass = require('gulp-sass');

gulp.task('sass', function () {
    return gulp.src('./bulma/bulma.scss')
        .pipe(sass().on('error', sass.logError))
        .pipe(gulp.dest('./bulma/css'));
});
gulp.task('bulmaconvert', function () {
    return gulp.src(['node_modules/bulma/*.+(sass|scss)',
        'node_modules/bulma/sass/**/*.+(sass|scss)'
    ], { base: './node_modules/bulma/' })
        .pipe(converter({
            from: 'sass',
            to: 'scss',
            rename: true
        }))
        // Rename file paths in source files
        .pipe(replace('.sass"', '.scss"'))
        .pipe(gulp.dest('./bulma'));
});

// 3. gulp bulmaconvert
// 4. gulp sass

after runnig gulp bulmaconvert :

`events.js:182
throw er; // Unhandled 'error' event
^

Error: spawn sass-convert ENOENT
at exports._errnoException (util.js:1022:11)
at Process.ChildProcess._handle.onexit (internal/child_process.js:189:19)
at onErrorNT (internal/child_process.js:366:16)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9)`

any idea?