codeigniter 3 file upload method

Media.php

<?php defined('BASEPATH') OR exit('No direct script access allowed');
 
class Event extends MY_Controller{
    function __construct()
    {
        parent::__construct();

    }  
//$file is the file name from form input
  //example is <input type="file" name="my_image" >
  //so $file = "my_image"
  //this for codeigniter
    function doUpload($file) {
        //configuration for upload your images
        $imagePath = realpath(APPPATH . '../assets/uploads/events');
        $config = array(
            'file_name'     => time().uniqid(),
            'allowed_types' => 'jpg|jpeg|png|gif',
            'max_size'      => 3000,
            'overwrite'     => FALSE,
            'upload_path'
            =>$imagePath
        );
        $this->upload->initialize($config);
        $errCount = 0;//counting errrs
        $data=[];
        if (!$this->upload->do_upload($file))
        {
            $error = $this->upload->display_errors();
            $theImages[] = array(
                'errors'=> $error
            );//saving arrors in the array
            $this->session->set_flashdata('error', $error);
        }
        else
        {
            $filename = $this->upload->data();
            $theImages[] = array(
                'fileName'=>$filename['file_name']
            );
            $params = array('file_name' => '/assets/uploads/events/'.$filename['file_name'], );
            $data = '/assets/uploads/events/'.$filename['file_name'];
        }//if file uploaded
        return($data);

        }
    
}