  import copy
  
  from django.test import SimpleTestCase
  from django.utils.datastructures import (
      DictWrapper, ImmutableList, MultiValueDict, MultiValueDictKeyError,
      OrderedSet,
  )
  
  
  class OrderedSetTests(SimpleTestCase):
  
 
</s> remove from django.utils.datastructures import ImmutableList, MultiValueDict
 </s> add from django.utils.datastructures import (
    CaseInsensitiveMapping, ImmutableList, MultiValueDict,
) </s> remove from django.http.request import split_domain_port
 </s> add from django.http.request import HttpHeaders, split_domain_port </s> remove * ...
 </s> add * Added :attr:`.HttpRequest.headers` to allow simple access to a request's
  headers.
    CaseInsensitiveMapping, DictWrapper, ImmutableList, MultiValueDict,
    MultiValueDictKeyError, OrderedSet,
  import copy
  
  from django.test import SimpleTestCase
  from django.utils.datastructures import (
    CaseInsensitiveMapping, DictWrapper, ImmutableList, MultiValueDict,
    MultiValueDictKeyError, OrderedSet,
    CaseInsensitiveMapping, DictWrapper, ImmutableList, MultiValueDict,
    MultiValueDictKeyError, OrderedSet,
  )
  
  
  class OrderedSetTests(SimpleTestCase):
  
keep keep keep keep replace replace keep keep keep keep keep
 Fixed #20147 -- Added HttpRequest.headers. 
tests/utils_tests/test_datastructures.py