def extract_conf_from(mod, conf=ModuleConfig(CONF_SPEC), depth=0, max_depth=2):
    for key, default_value in six.iteritems(conf):
        conf[key] = _get_key_from_module(mod, key, default_value)
    try:
        filtered_apps = [app for app in conf['apps'] if app not in BLACKLIST]
    except TypeError:
        pass
    except Exception as e:
        warnings.warn('Error %s during loading %s' % (e, conf['apps']))
    for app in filtered_apps:
        try:
            app_module = import_module(app)
            if app_module != mod:
                app_module = _get_correct_module(app_module)
                if depth < max_depth:
                    mod_conf = extract_conf_from(app_module, depth=depth+1)
                    for k, v in six.iteritems(mod_conf):
                        if k == 'config':
                            continue
                        if isinstance(v, dict):
                            conf[k].update(v)
                        elif isinstance(v, (list, tuple)):
                            conf[k] = merge(conf[k], v)
        except Exception as e:
            pass
    return conf