1👍
Your query returns a dictionary. You can get value in this way:
cont_rating_tmp = EmployerReviewContractor.objects.filter(
reviewed__id = cont.id
).aggregate(average=Avg('avg_rate'))
cont.rate=cont_rating_tmp["average"]
I copy a saple from django aggregation doc:
>>> from django.db.models import Max
>>> Book.objects.all().aggregate(Max('price'))
{'price__max': Decimal('81.20')} <--- the result (a dictionary)
Source:stackexchange.com