code: public function tf($ns, string $key, array $args = null, N2nLocale ...$n2nLocales): string {
  		$namespaces = array();
  		if (!is_array($ns)) {
  			$namespaces[] = $ns;
  		}
  
  		if (!is_array($ns) && $this->dbtextCollections[$ns]) {
  			return $this->dbtextCollections[$ns]->tf($key, $args, ...$n2nLocales);
  		}
  		
  		return $this->tc($ns, ...$n2nLocales)->tf($key, $args, ...$n2nLocales);
  	}
docs: Uses {@see DbtextCollection dbtextCollections} to translate a textblock.
  
  @see DbtextCollection::tf()
  @param string|string[] $ns
  @param string $key
  @param array|null $args
  @param N2nLocale[] ...$n2nLocale
  @return string