      DisallowedHost, ImproperlyConfigured, RequestDataTooBig,
  )
  from django.core.files import uploadhandler
  from django.http.multipartparser import MultiPartParser, MultiPartParserError
  from django.utils.datastructures import ImmutableList, MultiValueDict
  from django.utils.deprecation import RemovedInDjango30Warning
  from django.utils.encoding import escape_uri_path, iri_to_uri
  from django.utils.functional import cached_property
  from django.utils.http import is_same_domain, limited_parse_qsl
  
 
</s> remove     DictWrapper, ImmutableList, MultiValueDict, MultiValueDictKeyError,
    OrderedSet,
 </s> add     CaseInsensitiveMapping, DictWrapper, ImmutableList, MultiValueDict,
    MultiValueDictKeyError, OrderedSet, </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.
from django.utils.datastructures import (
    CaseInsensitiveMapping, ImmutableList, MultiValueDict,
)
      DisallowedHost, ImproperlyConfigured, RequestDataTooBig,
  )
  from django.core.files import uploadhandler
  from django.http.multipartparser import MultiPartParser, MultiPartParserError
from django.utils.datastructures import (
    CaseInsensitiveMapping, ImmutableList, MultiValueDict,
)
  from django.utils.deprecation import RemovedInDjango30Warning
  from django.utils.encoding import escape_uri_path, iri_to_uri
  from django.utils.functional import cached_property
  from django.utils.http import is_same_domain, limited_parse_qsl
  
keep keep keep keep replace keep keep keep keep keep
 Fixed #20147 -- Added HttpRequest.headers. 
django/http/request.py