public PresentersDto AddNewPresenter(PresenterCreationDTO newPresenter)
{
int id = Int32.Parse(Presenters.Max((presenter) => presenter.Id)) + 1;
PresentersDto presenterToAdd = new PresentersDto(id.ToString(), newPresenter.Name, newPresenter.BirthYear,
newPresenter.DeathYear);
Presenters.Add(presenterToAdd);
return(presenterToAdd);
}