Type an array of type any [] in angular 6

I need to type an object, so I do not get any [] in the agile 6. Well, on the get, I get this from the API:

{
    "error": false,
    "itens": [
        [
            {
                "operatorId": "819ee9cc-70b6-44dc-b9e8-afff8705142c",
                "name": "Vera Silva"
            },
            {
                "operatorId": "ccad3b40-c227-425e-b3b1-feedf6cfac2e",
                "name": "Catarina Silva"
            },
            {
                "operatorId": "68781a7b-ac4c-4a85-9f93-36dc5d65d1af",
                "name": "José da Silva"
            }
        ]
    ],
    "message": ""
}

In my Component I rebooted so (getAll)

import { Component, OnInit } from '@angular/core';
import { Operator } from '../operator';
import { OperatorService } from '../operator.service';

export interface getOperator{
  Id: string;
  Name: string;
}

@Component({
  selector: 'app-operators',
  templateUrl: './operators.component.html',
  styleUrls: ['./operators.component.css'],
  providers: [OperatorService]
})

export class OperatorsComponent implements OnInit {

   displayedColumns: string[] = ['codigo', 'nome'];

    public message: string;
    public dataSource: any[];

    constructor
    (
        private _operService: OperatorService
    ) 
    {
        //this.message = 'Hello from HomeComponent constructor';
    }

  ngOnInit() {

  this._operService
      .getAll<any[]>()
      .subscribe((data: any[]) => {
        debugger;
        this.dataSource = data.itens
      });
  }
}

Notice that my dataSource receives an array of type any [] . This is causing my mat-table in my html not to be populated. My html

div>
  <table mat-table [dataSource] = "dataSource" class="mat-elevation-z8">

     <ng-container matColumnDef="codigo">
       <th mat-header-cell *matHeaderCellDef> Codigo </th>
       <td mat-cell *matCellDef="let oper"> {{oper.Id}} </td>
    </ng-container>

    <ng-container matColumnDef="nome">
      <th mat-header-cell *matHeaderCellDef> Nome </th>
      <td mat-cell *matCellDef="let oper"> {{oper.Name}} </td>
    </ng-container>

    <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
    <tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
    </table>
</div>

The idea would be to type instead of passing any any [], but I do not know how I do it? I would create on the angular side a class like this: error, items, message ? and put it in the place of Any, type:

export class Item{
error: boolean;
itens: array de alguma coisa;
message: string;
}

Would that be?

EDIT1

Following the advice of colleague Gustavo Santos, I did the following:

export class Operation{
    error: boolean;
    itens: Array<Itens[]>;
    message: string;
}

export class Itens{
    objectId: string;
    name: string;
}

But when installing on Component, it says [ts] Property 'does not exist on type' Operation [] ', exactly here:

debugger;
this.dataSource = data.itens;

My Component looks like this:

import { Component, OnInit } from '@angular/core';
import { Operator } from '../operator';
import { OperatorService } from '../operator.service';
import { Operation } from '../model/operators/operations';

export interface getOperator{
  Id: string;
  Name: string;
}

@Component({
  selector: 'app-operators',
  templateUrl: './operators.component.html',
  styleUrls: ['./operators.component.css'],
  providers: [OperatorService]
})

export class OperatorsComponent implements OnInit {

   displayedColumns: string[] = ['codigo', 'nome'];

    public message: string;
    public dataSource: Operation[];

    constructor
    (
        private _operService: OperatorService
    ) 
    {        
    }

  ngOnInit() {

  this._operService
      .getAll<Operation[]>()
      .subscribe((data: Operation[]) => {
        debugger;
        this.dataSource = data.itens;
      });
  }
}