Why do I get: "Error: cannot find module sass" when I run "gulp" in terminal?

I'm trying to run a gulp task but when I go to Terminal > Run Task... > gulp it says No gulp task found. I run gulp in the terminal and I get the title's error.

which sass: /home/username/.nvm/versions/node/v17.4.0/bin/sass.

which node: /home/username/.nvm/versions/node/v17.4.0/bin/node.

which gulp: /home/username/.nvm/versions/node/v17.4.0/bin/gulp.

Gulp version:

CLI version: 2.3.0
Local version: 4.0.2

Gulp sass version: ^5.1.0.

My gulpfile.js; is in the root folder (as my styles.scss, styles.css, styles.min.css, package.json, package-lock.json and node_modules/), with the code:

// Sass configuration
var gulp = require('gulp');
var sass = require('gulp-sass')(require('sass'));

gulp.task('sass', function(cb) {
  gulp
    .src('*.scss')
    .pipe(sass())
    .pipe(
      gulp.dest(function(f) {
        return f.base;
      })
    );
  cb();
});

gulp.task(
  'default',
  gulp.series('sass', function(cb) {
    gulp.watch('*.scss', gulp.series('sass'));
    cb();
  })
);

I removed and re-installed gulp and gulp-sass but the result is the same.

I'm following these steps.

I fixed the problem by adding npm i --save-dev sass.