public IActionResult ClassStream(Guid?classId = null, Guid?sectionId = null, Guid?streamId = null)
 {
     try
     {
         var result = _classBusiness.ClassStream(classId, sectionId, streamId);
         return(Ok(result));
     }
     catch (Exception ex)
     {
         return(BadRequest(ex));
     }
 }