filter for union all model field (in query param) for django rest framework

union_django_filter_backend.py

from rest_framework import filters
from django.db.models import Q

class UnionFilterBackend(filters.BaseFilterBackend):
    """
    Filter that make union queryset with given query parametes
        and model filter wich defined in filter_fields
    Usage:
        [url]/?foo=bar&foo=baz&xyzzy=qux
        queryset will be : [queryset].filter(foo=bar or foo=baz or xyzzy=qux)
    """
    def filter_queryset(self, request, queryset, view):
        field_lookups = None
        for field in view.filter_fields:
            for filter_value in dict(request.query_params).get(field, []):
                if field_lookups: # union prev lookups with current filter_value
                    field_lookups = field_lookups | Q(**{field:filter_value})
                else: # fill first lookup
                    field_lookups = Q(**{field:filter_value})
        if field_lookups:
            queryset = queryset.filter(field_lookups)
        return queryset