Function authenticate 

pub async fn authenticate(
    code: String,
    client_secret: String,
    client_id: String,
    redirect_uri: String,
) -> Result<AuthResponse, Error>

Transform the code in a token, the result is AuthResponse. code expires so be very light on this operation. The response token will be level client.

client_secret, client_id and redirect_uri are found at https://genius.com/api-clients.

Errors

If the code is not valid or the request fails.