@ask.launch
def launch():
    content_type = "application/x-www-form-urlencoded;charset=utf-8"
    client_id = "amzn1.application-oa2-client.6a48deff5a334b37b23e28b39bb5a408"
    client_secret = "5928cafa0226a324f77bc65623abb922878183f5d863cc1cb643085391c24906"
    scope = "alexa::proactive_events"
    grant_type = "client_credentials"

    data = {"grant_type": grant_type, "client_id": client_id, "client_secret": client_secret, "scope": scope}
    r = requests.post("https://api.amazon.com/auth/O2/token", data=data, headers={"content-type": content_type})

    speech = render_template("welcome")
    reprompt = render_template("welcome_reprompt")
    return question(speech).reprompt(reprompt)

{'error_description': 'The request has an invalid parameter : scope', 'error': 'invalid_scope'}