text: Question :
  Caught an exception while rendering:
  Reverse for ‘products.views.’filter_by_led’ with arguments ‘()’ and
  keyword arguments ‘{}’?
  Answer #1:
  There are 3 things I can think of off the top of my head:
  - Just used named urls, it’s more robust and maintainable anyway
  Try using
  django.core.urlresolvers.reverseat the command line for a (possibly) better error
  from django.core.urlresolvers import reverse reverse('products.views.filter_by_led')
  Check to see if you have more than one url that points to that view
  Answer #2:
  Shell calls to reverse (as mentioned above) are very good to debug these problems, but there are two critical conditions:
  - you must supply arguments that matches whatever arguments the view needs,
  - these arguments must match regexp patterns..
  'show_cookies', kwargs={'url_id':123,'hostname': 'aaa'}) '/cookies/aaa/123'reverse(
  Now it worked, but…
  'show_cookies', kwargs={'url_id':'x','hostname': ''}) NoReverseMatch: Reverse for 'show_cookies' with arguments '()' and keyword arguments '{'url_id': 'x', 'hostname': ''}' not found.reverse( ‘news.views.year_archive’ yearvar %}
  So I used it in a similar way in my HTML template:
  {% url ‘show.
  Answer #3:
  You need single quotes around the view name
  {% url 'viewname' %}
  instead of
  {% url viewname %}
  Answer #4:
  I had a similar problem and the solution was in the right use of the ‘$’ (end-of-string) character:
  My main url.py looked like this (notice the $ character):
  urlpatterns = [ url(r'^admin/', include(admin.site.urls )), url(r'^$', include('card_purchase.urls' )), ]
  and my url.py for my card_purchases app said:
  urlpatterns = [ url(r'^$', views.index, name='index'), url(r'^purchase/$', views.purchase_detail, name='purchase') ]
  I used the ‘$’ twice. So a simple change worked:
  urlpatterns = [ url(r'^admin/', include(admin.site.urls )), url(r'^cp/', include('card_purchase.urls' )), ]
  Notice the change in the second url! My url.py for my card_purchases app looks like this:
  urlpatterns = [ url(r'^$', views.index, name='index'), url(r'^purchase/$', views.purchase_detail, name='purchase') ]
  Apart from this, I can confirm that quotes around named urls are crucial!
  Answer #5:
  In case it helps someone, I had a similar issue and the error was because of two reasons:
  Answer #6:
  I don’t think you need the trailing slash in the URL entry. Ie, put this instead:
  (r'^led-tv$', filter_by_led ),
  This is assuming you have trailing slashes enabled, which is the default.
  Answer #7:
  {% url 'polls:create' poll.id %}