public ExaminationResult FilterExamination(SearchFilter filter)
        {
            if (string.IsNullOrEmpty(_examinationType))
            {
                throw new InvalidOperationException("The repository is not initialized");
            }

            // get examination from {_examinationType} table
            return(new ExaminationResult
            {
                Content = $"{InstanceName}: FilterExamination: type = {_examinationType}, {filter.GetLog()}. Using ConnectionString = {_connectionString}"
            });
        }