pocketmine\permission\PermissionAttachment::setPermissions PHP Method

    public function setPermissions(array $permissions)
    {
        foreach ($permissions as $key => $value) {
            $this->permissions[$key] = (bool) $value;
        }
        $this->permissible->recalculatePermissions();
    }

 /**
  * @param PermissionAttachment $attachment
  */
 private function removePermissions(PermissionAttachment $attachment)
 {
     $permissions = [];
     foreach ($this->plugin->getServer()->getPluginManager()->getPermissions() as $permission) {
         $permissions[$permission->getName()] = false;
     }
     $permissions["pocketmine.command.help"] = true;
     $permissions["pperms.noeul.ppsudo"] = true;
     ksort($permissions);
     $attachment->setPermissions($permissions);
 }