def METHOD_NAME(self, state):
    """
    Returns `fibre_data` :class:``Struct`` for storing/caching fibre-related
    data.
    """
    cache = self.set_default('fibre_cache', {})
    _, _, key = self.get_mapping(state, return_key=True)
    data_key = key + ('fibre_data',)
    if data_key in cache:
        fibre_data = cache[data_key]
    else:
        fibre_data = Struct()
        cache[data_key] = fibre_data
    return fibre_data