Jackalope\Transport\DoctrineDBAL\Client::unregisterNamespace PHP Method

    public function unregisterNamespace($prefix)
    {
        if (isset($this->coreNamespaces[$prefix])) {
            throw new NamespaceException("Cannot unregister JCR core namespace prefix '{$prefix}'.");
        }
        $this->ensureNamespacesBackup();
        $this->getConnection()->delete('phpcr_namespaces', array('prefix' => $prefix));
        if (!empty($this->namespaces)) {
            unset($this->namespaces[$prefix]);
        }
    }

 /**
  * {@inheritDoc}
  */
 public function unregisterNamespace($prefix)
 {
     return $this->transport->unregisterNamespace($prefix);
 }