code: def netrc_from_env() -> Optional[netrc.netrc]:
      
      netrc_env = os.environ.get('NETRC')
  
      if netrc_env is not None:
          netrc_path = Path(netrc_env)
      else:
          try:
              home_dir = Path.home()
          except RuntimeError as e:  # pragma: no cover
              # if pathlib can't resolve home, it may raise a RuntimeError
              client_logger.debug('Could not resolve home directory when '
                                  'trying to look for .netrc file: %s', e)
              return None
  
          netrc_path = home_dir / (
              '_netrc' if platform.system() == 'Windows' else '.netrc')
  
      try:
          return netrc.netrc(str(netrc_path))
      except netrc.NetrcParseError as e:
          client_logger.warning('Could not parse .netrc file: %s', e)
      except OSError as e:
          # we couldn't read the file (doesn't exist, permissions, etc.)
          if netrc_env or netrc_path.is_file():
              # only warn if the environment wanted us to load it,
              # or it appears like the default file does actually exist
              client_logger.warning('Could not read .netrc file: %s', e)
  
      return None
docs: Attempt to load the netrc file from the path specified by the env-var
      NETRC or in the default location in the user's home directory.
  
      Returns None if it couldn't be found or fails to parse.