Mocking GraphQL, MockList genertes only two items in the array

I am trying to generate a list of 10 items in my GraphQL mock server like this:

import { makeExecutableSchema, addMockFunctionsToSchema, MockList } from 'graphql-tools';
import casual from 'casual';
import typeDefs from './schema.graphql';

export const schema = makeExecutableSchema({ typeDefs });

const mocks = {
  File: () => ({
    path: casual.random_element([
      '/assets/images/cars/1.JPG',
      '/assets/images/cars/2.JPG',
      '/assets/images/cars/3.JPG',
      '/assets/images/cars/4.JPG',
      '/assets/images/cars/5.JPG',
      '/assets/images/cars/6.JPG',
      '/assets/images/cars/7.JPG',
    ]),
  }),
  UsedCar: () =>
    new MockList(10, () => ({
      price: casual.integer(10000, 99999999),
      year: casual.integer(1990, 2017),
    })),
};

// This function call adds the mocks to your schema!
addMockFunctionsToSchema({ schema, mocks });

But I always get two used cars I don't know why. Can anyone help?

Regards, Mostafa