def _get_param_value(params, key_name):
    """
    Get parameter value from Cloudformation Stack Parameters.

    :param outputs: Cloudformation Stack Parameters
    :param key_name: Parameter Key
    :return: ParameterValue if that parameter exists, otherwise None
    """
    return next((i.get("ParameterValue") for i in params if i.get("ParameterKey") == key_name), None)