How to select your default id

[punpom]

module.exports = {
    name: "profile",
    code: `
    $author[$username[$mentioned[1;yes]]; $userAvatar[$mentioned[1; yes]]]
    $thumbnail[$userAvatar[$mentioned[1;yes]]]
    `
}

When I make this command without mentioning someone I get the following error message:

AoiError: $userAvatar: Invalid User ID Provided In [undefined] 
 { 
   lineNumber : 5,
   line : `undefined`,
   path : "undefined" 
 }

And I want that when no one is mentioned it is the author of the message that is selected, how does that work?

[USERSATOSHI]

$mentioned[1;yes]
yes means if no-one was mentioned then return author's id