private function dumpKeys(IHaveAnSSHKey $user)
 {
     $ssh_key_id = 0;
     $user_name = $user->getUserName();
     foreach ($user->getAuthorizedKeysArray() as $key) {
         $filePath = $this->getKeyDirPath() . '/' . $user_name . '@' . $ssh_key_id . '.pub';
         $this->writeKeyIfChanged($filePath, $key);
         $ssh_key_id++;
     }
     $this->removeUserExistingKeysFromAGivenKeyId($user_name, $ssh_key_id);
 }