lib/Dropbox/OAuth1AccessToken.php
static function checkArg($argName, $argValue)
    {
        if (!($argValue instanceof self)) Checker::throwError($argName, $argValue, __CLASS__);
    }
static function checkArg($argName, $argValue)
    {
        if (!($argValue instanceof self)) Checker::throwError($argName, $argValue, __CLASS__);
    }
Use this to check that a function argument is of type `AppInfo`

@internal