def create_token_request_payload(auth_code, redirect_uri, optional_token_request_params):
    """
    Construct payload for access token request
    """
    token_request_payload = {
        # Don't include client_id param: Verizon doesn't like it
        'grant_type': 'authorization_code',
        'code': auth_code,
        'redirect_uri': redirect_uri,
        **optional_token_request_params
    }
    return token_request_payload