Angular9 sanitizer: Sanitizer return null

I try to import and use Sanitizer as follow but then I get null when try to console.log sanitizer

import { Component, OnInit, Sanitizer, SecurityContext } from '@angular/core';

@Component({
  selector: 'app-summarise-written-text',
  templateUrl: './summarise-written-text.component.html',
  styleUrls: ['./summarise-written-text.component.css']
})

export class SummariseWrittenTextComponent implements OnInit {
  constructor(
    private sanitizer: Sanitizer,
  ) { }

  ngOnInit(): void {
    console.log(this.sanitizer.sanitize(SecurityContext.HTML, '<div>some text here\n but error</div>'));
  }