public static function unPreBackSlash($str, $unify = false)
    {
        return self::_slash($str, '\\', true, false, $unify);
    }
public static function unPreBackSlash($str, $unify = false)
    {
        return self::_slash($str, '\\', true, false, $unify);
    }
public static function unPreBackSlash ( $ str , $ unify = false ) { return self :: _slash ( $ str , '\\' , true , false , $ unify ) ; }
remove potential backslash from the front of the string.

@access public
@param  string  $str    the string to be unbackslashed
@param  boolean $unify  set true to unify all slashes in $str
@return string          the unbackslashed string
remove potential backslash from the front of the string .