Ammended my fix for carltongibson#115

Instead of moving bailout code, added condition on list length, to prevent unpacking of empty list.

django_filters/filters.py

@@ -63,17 +63,15 @@ def field(self):
         return self._field
 
     def filter(self, qs, value):
-        if value in ([], (), {}, None, ''):
-            return qs
-
-        if isinstance(value, (list, tuple)):
+        if isinstance(value, (list, tuple)) and len(value)==2:
             lookup = six.text_type(value[1])
             if not lookup:
-                lookup = 'exact'  # fallback to exact if lookup is not provided
+                lookup = 'exact' # fallback to exact if lookup is not provided
             value = value[0]
         else:
             lookup = self.lookup_type
-
+        if value in ([], (), {}, None, ''):
+            return qs
         qs = qs.filter(**{'%s__%s' % (self.name, lookup): value})
         if self.distinct:
             qs = qs.distinct()