	public static function simple($input)
	{
		return empty($str) ? '' : pts_strings::keep_in_string($input, pts_strings::CHAR_LETTER | pts_strings::CHAR_NUMERIC | pts_strings::CHAR_DASH | pts_strings::CHAR_DECIMAL | pts_strings::CHAR_SPACE | pts_strings::CHAR_UNDERSCORE | pts_strings::CHAR_COMMA | pts_strings::CHAR_AT | pts_strings::CHAR_COLON);
	}
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.