def METHOD_NAME(self, index: int) -> Tuple[TimeSeries, slice, slice]:
    scope_id, tgt_head = self.windows[index]
    tgt_tail = tgt_head + self.horizon
    ctx_tail = tgt_head - self.gap
    ctx_head = None if self.context is None else ctx_tail - self.context
    ctx_window = slice(ctx_head, ctx_tail)
    tgt_window = slice(tgt_head, tgt_tail)
    return self.corpus[scope_id], ctx_window, tgt_window