class Program
{
    private readonly IFooService _service;

    public Program(IFooService service)
    {
        _service = service;
    }

    void Main(string[] args)
    {
        RemoveOldEntries();
    }

    public void RemoveOldEntries()
    {
        _service.DeleteOldItems(DateTime.UtcNow);
    }
}

Program does not contain a static 'Main' method suitable for an entry point