null check simplified

smash/web/importer/importer.py

@@ -50,9 +50,8 @@ class Importer(EtlCommon):
         logging.getLogger('').removeHandler(warning_counter)
 
     def import_study_subject(self, study_subject: StudySubject):
-        db_study_subjects = StudySubject.objects.filter(nd_number=study_subject.nd_number)
-        if db_study_subjects.count() > 0:
-            db_study_subject = db_study_subjects.first()
+        db_study_subject = StudySubject.objects.filter(nd_number=study_subject.nd_number).first()
+        if db_study_subject is not None:
             for field in Subject._meta.get_fields():
                 if field.get_internal_type() == "CharField" or \
                         field.get_internal_type() == "DateField" or \