public function run($request) {
		$units = array ('seconds', 'hours', 'minutes', 'days', 'weeks', 'months', 'years');
		$unit = $request->requestVar('unit');
		if(!$unit || !in_array($unit, $units)) {
			throw new RuntimeException("Please specify a 'unit' parameter. Possible values: ".implode(', ', $units));
		}

		$count = $request->requestVar('count');
		if(!$count) {
			throw new RuntimeException("Please specify a 'count' parameter for the number of $unit you want to to keep.");
		}

		$stamp = strtotime("-{$count} $unit");
		$date = date('Y-m-d H:i:s');

		$count = SentEmail::get()->filter(array(
			'Created:LessThan' => $date
		))->count();
		
		DB::query("DELETE FROM \"SentEmail\" WHERE Created < '$date'");

		echo "Deleted $count records.";
	}