async def form(self, *, encoding: Optional[str] = None) -> List[Tuple[str, str]]:
        """Like read(), but assumes that body parts contain form urlencoded data."""
        data = await self.read(decode=True)
        if not data:
            return []
        if encoding is not None:
            real_encoding = encoding
        else:
            real_encoding = self.get_charset(default="utf-8")
        return parse_qsl(
            data.rstrip().decode(real_encoding),
            keep_blank_values=True,
            encoding=real_encoding,
        )
Like read(), but assumes that body parts contain form urlencoded data.
lib/aiohttp/multipart.py