public function search($params)
 {
     $query = Country::find();
     $dataProvider = new ActiveDataProvider(['query' => $query]);
     if (!($this->load($params) && $this->validate())) {
         return $dataProvider;
     }
     $query->andFilterWhere(['country_id' => $this->country_id, 'last_update' => $this->last_update]);
     $query->andFilterWhere(['like', 'country', $this->country]);
     return $dataProvider;
 }