Grant type None is not supported

[TheCherry]

Python 3.8.3
aiohttp 3.7.4.post0
aiohttp-oauth2 0.0.5

If I try to use aiohttp-oauth2 with discord I get this error:
{"error": "unsupported_grant_type", "error_description": "Grant type None is not supported"}

This is my Code:

    app.add_subapp(
        "/auth/discord/",
        oauth2_app(
            client_id=00000000000000000000000000000,
            client_secret="XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
            authorize_url="https://discord.com/api/oauth2/authorize?client_id=0000000000&redirect_uri=http%3A%2F%DOMAIN.DE%3A8080%2Fdiscord%2Fcallback&response_type=code&scope=identify%20email%20connections%20guilds",
            token_url="https://discordapp.com/api/v6/oauth2/token",
            scopes=['identify']
        ),
    )

[mattrasband]

Thank you for sharing this, I don't have the bandwidth to investigate until August - so please don't take silence as ignoring it!