Just adding this for multiple filters attaching to Q object, if someone might be looking to it. If a Q object is provided, it must precede the definition of any keyword arguments. Otherwise its an invalid query. You should be careful when doing it.

an example would be

from django.db.models import Q
User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True),category='income')

Here the OR condition and a filter with category of income is taken into account

from django.db.models import Q
criterion1 = Q(question__contains="software")
criterion2 = Q(question__contains="java")
q = Question.objects.filter(criterion1 & criterion2)