Custom validator is not working in FormGroup in Angular 10

Question

In my reactive form I have two password fields. Two match the two field's value I have created a custom validator and then assign that validator in form group in ts file. The code is below:

this.registerForm = new FormGroup({
      title: new FormControl("", Validators.required),
      firstName: new FormControl("", Validators.required),
      lastName: new FormControl("", Validators.required),
      password: new FormControl("", [Validators.required, Validators.minLength(6)]),
      confirmPassword: new FormControl("", Validators.required),
      acceptTerms: new FormControl("", Validators.required)      
    },
    {
      validator: MustMatch('password', 'confirmPassword')
    });

Must Match Validator code:

export function MustMatch(controlName: string, matchingControlName: string) {
  return (formGroup: FormGroup) => {
    const control = formGroup.controls[controlName];
    const matchingControl = formGroup.controls[matchingControlName];

    if (matchingControl.errors && !matchingControl.errors.mustMatch11111) {
      // return if another validator has already found an error on the matchingControl                           
      return;
    }

    // set error on matchingControl if validation fails
    if (control.value !== matchingControl.value) {
      matchingControl.setErrors({ mustMatch11111: true });
    } else {
      matchingControl.setErrors(null);
    }
  }
}

But MustMatch is showing error which is below:

Argument of type '{ validator: (formGroup: FormGroup) => void; }' is not assignable to parameter of type 'ValidatorFn | ValidatorFn[] | AbstractControlOptions'. Object literal may only specify known properties, and 'validator' does not exist in type 'ValidatorFn | ValidatorFn[] | AbstractControlOptions'.

66       validator: MustMatch('password', 'confirmPassword')

As I am new to angular, can anyone please help me to solve the problem.