old_contents: import asyncio
  from typing import Mapping, Tuple, Any
  
  import httpx
  
  from . import abc as gh_abc
  
  
  class GitHubAPI(gh_abc.GitHubAPI):
      def __init__(self, client: httpx.AsyncClient, *args: Any, **kwargs: Any) -> None:
          self._client = client
          super().__init__(*args, **kwargs)
  
      async def _request(
          self, method: str, url: str, headers: Mapping[str, str], body: bytes = b""
      ) -> Tuple[int, Mapping[str, str], bytes]:
          """Make an HTTP request."""
          response = await self._client.request(
              method,
              url,
              # Reason: see discussion at https://github.com/brettcannon/gidgethub/pull/122#issuecomment-633738024.
              # httpx 0.13.1 updated the HeaderTypes and it is acting invariant, causing our Mapping[str, str] to be
              # technically incompatible with their Mapping[Union[str, bytes], Union[str, bytes]].
              headers=dict(headers),  # type: ignore
              data=body,
          )
          return response.status_code, response.headers, response.content
  
      async def sleep(self, seconds: float) -> None:
          """Sleep for the specified number of seconds."""
          await asyncio.sleep(seconds)
  
new_contents: import asyncio
  from typing import Mapping, Tuple, Any
  
  import httpx
  
  from . import abc as gh_abc
  
  
  class GitHubAPI(gh_abc.GitHubAPI):
      def __init__(self, client: httpx.AsyncClient, *args: Any, **kwargs: Any) -> None:
          self._client = client
          super().__init__(*args, **kwargs)
  
      async def _request(
          self, method: str, url: str, headers: Mapping[str, str], body: bytes = b""
      ) -> Tuple[int, Mapping[str, str], bytes]:
          """Make an HTTP request."""
          response = await self._client.request(
              method, url, headers=dict(headers), data=body
          )
          return response.status_code, response.headers, response.content
  
      async def sleep(self, seconds: float) -> None:
          """Sleep for the specified number of seconds."""
          await asyncio.sleep(seconds)
  
subject: Fix a typing warning from mypy involving httpx (#125)