[Observium] how to disable mib via config.php?

in default.inc.php is: $config['mibs']['EtherLike-MIB']['enable'] = 1;

I try in config.php $config['mibs']['EtherLike-MIB']['disable'] = 1; or $config['mibs']['EtherLike-MIB']['enable'] = 0; But it don't disable this mib. How to disable mib ? Thanks