AsyncGetToken = asyncify(authentication.GetToken)

...

    @property
    async def client(self) -> AsyncAuth0:
        """
        This property method returns an instance of AsyncAuth0. If the instance
        does not exist, it creates a new one using the domain and access
        token obtained from the _get_auth0_access_token method.
        """
        if self._client is None:
            auth0_token = await self._get_auth0_access_token()
            self._client = AsyncAuth0(self.domain, auth0_token)

        return self._client


    async def _get_auth0_access_token(self) -> str:
        """
        Performs the Auth0 authentication and returns the access token.
        """
        get_token = AsyncGetToken(self.domain, self.client_id, self.client_secret)
        response = await get_token.client_credentials_async(f"https://{self.domain}/api/v2/")

        return response["access_token"] # <--- fails here with TypeError: 'coroutine' object is not subscriptable