title: django chain list objects filter
body: <p>I want to collect all the models of all my applications and then filter them but I am having the following error :</p>
  
  <pre><code>AttributeError at /search 'list' object has no attribute 'filter'
  Request Method: GET Request
  URL:    http://127.0.0.1:8000/search?category=1&amp;submit=%D9%BE%DB%8C%D8%AF%D8%A7+%DA%A9%D9%86%21
  Django Version: 2.1.7 Exception Type:   AttributeError Exception Value: 
  'list' object has no attribute 'filter' Exception
  </code></pre>
  
  <p><strong>views.py</strong></p>
  
  <pre><code>from django.shortcuts import render
  from app_adventure.models import *
  from app_cultural.models import *
  from app_children.models import *
  from app_base.choices import Tour_type_choices, Destination_choices, Day_choices, Month_choices
  from itertools import chain
  
  
  # Create your views here.
  
  
  # search
  
  
  def search(request):
      adventure = AdventureTor.objects.all()
      cultural = CulturalTor.objects.all()
      children = ChildTor.objects.all()
      queryset_list = list(chain(adventure, cultural, children))
  
      # search by category
      if 'category' in request.GET:
          category = request.GET['category']
          if category:
              queryset_list = queryset_list.filter(category__icontains=category)  # mitonest iexact bashe
  
      context = {
          'Tour_type_choices': Tour_type_choices,
          'Destination_choices': Destination_choices,
          'Day_choices': Day_choices,
          'Month_choices': Month_choices,
          'search': queryset_list,
      }
  
      return render(request, 'search/search.html', context)
  </code></pre>