Map::readProviderFromBlock

static function readProviderFromBlock(Block $block): void
{
	self::$provider = self::PROVIDER_DEFAULT;
	$content = $block->getContent();

	if (preg_match(
		self::PROVIDER_REGEXP,
		$content,
		$matches
	))
	{
		$provider = $matches[1];
		if ($provider === self::PROVIDER_GOOGLE || $provider === self::PROVIDER_YANDEX)
		{
			self::$provider = $provider;
		}
	}
}