'Load all fields specified by ``fields`` for the supplied ``xblocks``
and ``aside_types`` into this cache.
Arguments:
fields (list of str): Field names to cache.
xblocks (list of :class:`XBlock`): XBlocks to cache fields for.
aside_types (list of str): Aside types to cache fields for.'

def cache_fields(self, fields, xblocks, aside_types):

    block_field_state = self._client.get_many(self.user.username, _all_usage_keys(xblocks, aside_types))
    for user_state in block_field_state:
        self._cache[user_state.block_key] = user_state.state
