"Notice: Undefined property: CI_DB_mysqli_result::$num_rows" when accessing num_rows of a CodeIgniter result set object

I am trying to execute a select query in CodeIgniter like below:

public function validate()
{
    $username = $this->security->xss_clean($this->input->post('username'));
    $password = $this->security->xss_clean($this->input->post('password1'));
    $type = $this->security->xss_clean($this->input->post('utype'));
    $password = md5($password);

    $this->db->select('*');
    $this->db->from('ci_users');
    $this->db->where('email', $username);
    $this->db->where('password', $password);
    $this->db->where('utype', $type);
    
    // Run the query
    $query = $this->db->get();
    
    // Let's check if there are any results
    if($query->num_rows == 1)
    {
        // more scripting
    } else {
        echo "OOPS some error";
    }
}

It is always showing oops some error, even I am enter correct username and password. why select query not run? I have done something wrong.

You are used :

if($query->num_rows == 1)

Correction is like bellow :

if($query->num_rows() == 1)