fix logic

    return default

def check_multi_environment(env_var_multi, multi_value, env_var, default):

def check_multi_environment(env_var_multi, multi_value, env_var, default=None):

    """ Check if the mod environment variable exists,

    if so, return that. If not, check if the vanilla variable

    has been specified and return that value instead.

    :param env_var: the vanilla environment variable to look for

    :param default: the vanilla environment variable default value

    """

    # check for existence of new var, if it exists, set environment

    # return multi value

    if str(env_var_multi) in os.environ:

        check_environment(env_var_multi, multi_value)

        return os.environ[env_var_multi]

    # set environment anyways for mutli

    os.environ[env_var_multi] = multi_value

        return check_environment(env_var_multi, multi_value)

    # set environment for vanilla and return vanilla

    check_environment(env_var, default)

    return os.environ[env_var]

    return check_environment(env_var, default)