public TagStatistics(string name, RemarksCountStatistics remarks = null)
 {
     if (name.Empty())
     {
         throw new ArgumentException("Category name can not be empty.", nameof(name));
     }
     Name    = name;
     Remarks = remarks ?? new RemarksCountStatistics();
 }
 public UserStatistics(string userId, string name, RemarksCountStatistics remarks = null)
 {
     if (userId.Empty())
     {
         throw new ArgumentException("User id can not be empty.", nameof(name));
     }
     if (name.Empty())
     {
         throw new ArgumentException("User name can not be empty.", nameof(name));
     }
     UserId  = userId;
     Name    = name;
     Remarks = remarks ?? new RemarksCountStatistics();
 }