php – Codeigniter中错误的含义：“致命错误：无法重新声明类My

Fatal error: Cannot redeclare class My_connection in C:wampwwwmvcsmscapplicationmodelsmy_connection.php on line 38

我创建了一个模型My_connection.我将此方法调用到我的控制器的构造函数中.
每个错误都有意义.这个错误背后的原因是什么？
请告诉错误的含义.可能是什么原因.我已经宣读了与此有关的许多问题.所有问题和答案都有所不同.他们试图纠正代码.我想知道原因.
请帮助相关问题.

<?php
class My_connection extends CI_Model{
public function __construct(){
    parent::__construct();
}

public function is_connected(){
    $session_id=$this->session->userdata('session_id');
    $session_username=$this->session->userdata('username');
    $session_password=$this->session->userdata('password');
    $this->db->select('session_id');
    $this->db->from('ci_sessions');
    $this->db->where('session_id',$session_id);
    $ses_query=$this->db->get();
    if($ses_query->num_rows>0){
    foreach($ses_query->rows as $row){
    $session_db_id=$ses_query->row();   
    }
    }
    $this->db->select('username','password');
    $this->db->from('users');
    $this->db->where('username',$session_username);
    $user_query=$this->db->get();
    if($user_query->num_rows()>0){
    foreach($user_query->result() as $row){
    $password=$row->password;
    $username=$row->username;   
    }
    }

    if( md5($password)==$session_password AND $username==$session_username AND  $session_db_id==$session_id){
        return TRUE;
    }
    else {
        return FALSE;
    }`enter code here`
}
}
/**
* End of file my_connection.php
* Location: application/models/my_connection.php
*/`

最后一行是38.根据错误.我没理解解决它.