message: style(typegoose): remove non-null assertion
diff: @@ -201,11 +201,12 @@ export function addModelToTypegoose<U extends AnyParamConstructor<any>, QueryHel
  */
  export function deleteModel(name: string) {
  assertion(typeof name === 'string', new TypeError('name is not an string! (deleteModel)'));
  - assertion(models.has(name), new Error(`Model "${name}" could not be found`));
  + const model = models.get(name);
  + assertion(model, new Error(`Model "${name}" could not be found`));
  logger.debug('Deleting Model "%s"', name);
  - models.get(name)!.db.deleteModel(name);
  + model.db.deleteModel(name);
  models.delete(name);
  constructors.delete(name);
  