old_contents: from typing import Any, Callable, Dict, List, Tuple
  try:
      from typing_extensions import Protocol
  except ImportError:
      from typing import Protocol
  
  StrHeaderListType = List[Tuple[str, str]]
  RawHeaderListType = List[Tuple[bytes, bytes]]
  HeaderDictType = Dict[str, Any]
  ParamDictType = Dict[str, str]
  AddNoteMethodType = Callable[..., None]
  
  
  class HttpResponseExchange(Protocol):
      def response_start(
          self, status_code: bytes, status_phrase: bytes, res_hdrs: RawHeaderListType
      ) -> None:
          ...
  
      def response_body(self, chunk: bytes) -> None:
          ...
  
      def response_done(self, trailers: RawHeaderListType) -> None:
          ...
  
new_contents: from typing import Any, Callable, Dict, List, Tuple
  try:
      from typing_extensions import Protocol
  except ImportError:
      from typing import Protocol # type: ignore
  
  StrHeaderListType = List[Tuple[str, str]]
  RawHeaderListType = List[Tuple[bytes, bytes]]
  HeaderDictType = Dict[str, Any]
  ParamDictType = Dict[str, str]
  AddNoteMethodType = Callable[..., None]
  
  
  class HttpResponseExchange(Protocol):
      def response_start(
          self, status_code: bytes, status_phrase: bytes, res_hdrs: RawHeaderListType
      ) -> None:
          ...
  
      def response_body(self, chunk: bytes) -> None:
          ...
  
      def response_done(self, trailers: RawHeaderListType) -> None:
          ...
  
subject: fix typecheck