local variable 'submission' referenced before assignment - django

Question

I encounter this error for my django project. my app is called "scoresubmission"
basially i have a feature in the website to allow user download report.
So in my views.py file i have report function and import report.py file, where it shows how report is built
It shows the error happens in this line of code:
submission=Submission.objects.get(month=month,year=reportyear,program=program)
Views.py
def report(request):
from scoresubmission.report import reportA, reportB, reportC
reportType = request.POST["reportType"]
reportYear = int(request.POST["reportYear"])
if reportType == 'a':
report_content = reportA(reportYear)
response = HttpResponse(report_content, content_type="text/csv")
response['Content-Disposition'] = 'inline; filename=5SAuditYearlySummaryReport_%d.xlsx' %reportYear
report.py where it has the relevant code
for facility in facilities:
worksheet.write(row,col,facility.name,facility_format)
for i in range(12): # 12 months
month=i+1
programs=Program.objects.filter(facility_id=facility.id)
avg_totalscore=0
count=1
for program in programs:
print(program)
try:
submission=Submission.objects.get(month=month,year=reportyear,program=program)
print(submission)
avg_score=Result.objects.filter(submission=submission).aggregate(Avg('NewScore'))
#print avg_score.get('NewScore__avg')
avg_totalscore=(avg_totalscore + avg_score.get('NewScore__avg'))/count
count=count+1
except submission.DoesNotExist:
pass
#print avg_totalscore
if avg_totalscore!=0:
worksheet.write(row,i+3,avg_totalscore,red_format)
else:
worksheet.write(row,i+3,'-',red_format)
Traceback (most recent call last):
File "C:\Users\CHLOZHAO\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
response = get_response(request)
File "C:\Users\CHLOZHAO\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
response = self.process_exception_by_middleware(e, request)
File "C:\Users\CHLOZHAO\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\CHLOZHAO\AppData\Local\Programs\Python\Python37\lib\site-packages\django\contrib\auth\decorators.py", line 21, in _wrapped_view
return view_func(request, *args, **kwargs)
File "C:\D Drive\5S Audit Website\my5saudit\scoresubmission\views.py", line 185, in report
report_content = reportA(reportYear)
File "C:\D Drive\5S Audit Website\my5saudit\scoresubmission\report.py", line 79, in reportA
except submission.DoesNotExist:
UnboundLocalError: local variable 'submission' referenced before assignment

Answer 1

In your except you need to refer to the class Submission, not the object, since it does not per se exists at that time:
try:
submission=Submission.objects.get(month=month,year=reportyear,program=program)
print(submission)
avg_score=Result.objects.filter(submission=submission).aggregate(Avg('NewScore'))
#print avg_score.get('NewScore__avg')
avg_totalscore=(avg_totalscore + avg_score.get('NewScore__avg'))/count
count=count+1
except Submission.DoesNotExist: # reference to the class, not the object
pass
If Sibmission.objects.get(..) fails, then the submission variable is never assigned, and hence submission.DoesNotExist makes no sense.
You acutally should never use the object, and always use the model class itself to refer to the DoesNotExist exception class.