PHP mkdir函数在调用时返回错误

I am trying to create 3 folders based on the email address of a user. I have one main folder, then the folder named after the email address, and finally a folder named images or tracks or chains. I am passing the paths to a function which should create them. However, nothing is happening. Can you please tell me what I am doing wrong?

public function createFolder($email){
    $this->email=$email;
    $this->pictureDirectoryPath = "../Uploads/$this->email/images";
    $this->uploadedTracksPath = "../Uploads/$this->email/tracks";
    $this->chainsPath = "../Uploads/$this->email/chains";

    //Calling the function doIt(path) to create the acutal directory.
    //The desired path is passed as a parameter

     doIt($this->pictureDirectoryPath);
     doIt($this->uploadedTracksPath);
     doIt($this->chainsPath);

}

//Function doIt() which is supposed to create a directory 
//However, nothing happens when it is called..
public function doIt($path){
    if (!mkdir($path, 0777, true)) {
            die('Failed to create folders...');
        }
}

To call functions/methods within a class you need to add $this-> or self:: depending on if it's static or not.

 $this->doIt($this->pictureDirectoryPath);
 $this->doIt($this->uploadedTracksPath);
 $this->doIt($this->chainsPath);