points for each feature map. Used in decoder.

        Args:
            spatial_shapes (`torch.LongTensor`):
                Spatial shapes of each feature map, has shape of `(num_feature_levels, 2)`.
            valid_ratios (`torch.FloatTensor`):
                Valid ratios of each feature map, has shape of `(batch_size, num_feature_levels, 2)`.
            device (`torch.device`):
                Device on which to create the tensors.
        Returns:
            `torch.FloatTensor` of shape `(batch_size, num_queries, num_feature_levels, 2)`
        r