original_string: public function get_participants(string $id_chat): ?array
    {
      if ( $this->check() ){
        return $this->db->get_field_values('bbn_chats_users', 'id_user', ['id_chat' => $id_chat]);
      }
      return null;
    }
code: public function get_participants(string $id_chat): ?array
    {
      if ( $this->check() ){
        return $this->db->get_field_values('bbn_chats_users', 'id_user', ['id_chat' => $id_chat]);
      }
      return null;
    }
code_tokens: public function get_participants ( string $ id_chat ) : ? array { if ( $ this -> check ( ) ) { return $ this -> db -> get_field_values ( 'bbn_chats_users' , 'id_user' , [ 'id_chat' => $ id_chat ] ) ; } return null ; }
docstring: Returns the participants of the given chat as an array of id_user.
  
  @param string $id_chat
  @return array|null
docstring_tokens: Returns the participants of the given chat as an array of id_user .