Undefined variable codeigniter model : guys i need to understand why the country_id variable isn't defined in 

**Model :**

    public function getCountry($country_id) {
		$this->db->select()->where('country_id', $country_id);
		$this->db->from('country');
		$query = $this->db->get();
        return $query->result(); 
		
	}

 **Controller :**

    $country_info = $this->country->getCountry($country_id);

Result :
   

    Message: Undefined variable: country_id
       Filename: localisation/Countries.php
       Line Number: 12