message: Remove `extractSingleMongoId`
diff: @@ -21,9 +21,7 @@ import * as fs from 'fs';
  import * as path from 'path';
  import ResponsiveImageService from '../services/ResponsiveImageService';
  import {IResponsiveImageData} from '../../../shared/models/IResponsiveImageData';
  -
  import {Picture} from '../models/mediaManager/File';
  -import {extractSingleMongoId} from '../utilities/ExtractMongoId';
  const coursePictureUploadOptions = {
  storage: multer.diskStorage({
  @@ -714,7 +712,7 @@ export class CourseController {
  throw new NotFoundError();
  }
  - const picture = await Picture.findById(extractSingleMongoId(course.image));
  + const picture = await Picture.findById(course.image);
  if (picture) {
  picture.remove();
  }
  @@ -783,7 +781,7 @@ export class CourseController {
  throw new BadRequestError('Forbidden format of uploaded picture: ' + mimeFamily);
  }
  - const picture = await Picture.findById(extractSingleMongoId(course.image));
  + const picture = await Picture.findById(course.image);
  if (picture) {
  picture.remove();
  }
  