<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_hashed_value(self, hash_value, store_key):
 """Add hashed value to the index. :param hash_value: The hashed value to be added to the index :type hash_value: str :param store_key: The key for the document in the store :type store_key: object """

        if self._unique and hash_value in self._index:
            raise NonUnique('Hash value {} already in index'.format(hash_value))
        if store_key not in self._index[hash_value]:
            self._index[hash_value].append(store_key)
        if hash_value not in self._reverse_index[store_key]:
            self._reverse_index[store_key].append(hash_value)