sass compilation error (wrong parser)?

Question

Sass

Good day.
I have a problem, please help. I apologize for my bad "French", I'm a beginner coder.
The essence of the problem is the following (I see the line where the error hits):
- there is a scss file with a cycle - @for $i from 1 through 12 {col-#{$i} {width: 8%;} }
- gulp-sass is installed, in gulpfile .js compile sass and scss to css -
var gulp = require('gulp'),
sass = require('gulp-sass');
gulp.task('sass', function () {
gulp.src(['app/sass/**/*.scss','app/sass/**/*.sass'])
.pipe(sass() )
.pipe(gulp.dest('app/css'))
});
Everything, it would seem, according to the textbook.
- You tried to parse SCSS with the standard CSS parser; try again with the postcss-scss
parser
What is the reason? I can't do it myself.