How to use the ngx-validators.PasswordValidators.specialCharacterRule function in ngx-validators

selector: 'app-reactive-password-validator',
  templateUrl: './password-validator.component.html',
  styleUrls: ['./password-validator.component.css']
})
export class ReactiveFormPasswordValidatorComponent implements OnInit {

  form: FormGroup;
  value: string;
  password = new FormControl('', Validators.compose([
    //Validators.required,
    PasswordValidators.repeatCharacterRegexRule(4),
    PasswordValidators.alphabeticalCharacterRule(1),
    PasswordValidators.digitCharacterRule(1),
    PasswordValidators.lowercaseCharacterRule(1),
    PasswordValidators.uppercaseCharacterRule(1),
    PasswordValidators.specialCharacterRule(1)
  ]));
  confirmPassword = new FormControl('');

  constructor(protected _fb: FormBuilder) { }

  ngOnInit() {
    this.form = this._fb.group({
      'newPassword': this.password,
      'confirmPassword': this.confirmPassword
    });

    this.form.setValidators(PasswordValidators.mismatchedPasswords());
  }

  getHintClass(formName: string, errorId: string): string {
    if (this.form.controls[formName].hasError('required')) {