original_string: public function retrieve_user_ids(string $id_option = null, string $id_user): ?array
    {
      return $this->_retrieve_ids($id_option, $id_user);
    }
code: public function retrieve_user_ids(string $id_option = null, string $id_user): ?array
    {
      return $this->_retrieve_ids($id_option, $id_user);
    }
code_tokens: public function retrieve_user_ids ( string $ id_option = null , string $ id_user ) : ? array { return $ this -> _retrieve_ids ( $ id_option , $ id_user ) ; }
docstring: Returns preferences' IDs from the option's ID and the given user ID
  
  @param null|string $id_option
  @param string $id_user
  @return array|null
docstring_tokens: Returns preferences IDs from the option s ID and the given user ID