public DateFormatter::getSampleDateFormats($langcode = NULL, $timestamp = NULL, $timezone = NULL)
Provides values for all date formatting characters for a given timestamp.
Parameters
string|null $langcode: (optional) Language code of the date format, if different from the site default language.
int|null $timestamp: (optional) The Unix timestamp to format, defaults to current time.
string|null $timezone: (optional) The timezone to use, if different from the site's default timezone.
Return value