Error in rownames(st_data[[st_assay]]@data) : no slot of name "data" for this object of class "Assay5", Possible Seurat v5.0 error

Hiya, got a problem here

traint_result <- CellTrek::traint(st_data = ST,
                                  sc_data = SC,
                                  sc_assay = 'RNA',
                                  norm = 'SCT',
                                  cell_names = 'subclass')

Finding transfer anchors... 
No variable features found for object2 in the object.list. Running FindVariableFeatures ...
Calculating gene variances
0%   10   20   30   40   50   60   70   80   90   100%
[----|----|----|----|----|----|----|----|----|----|
**************************************************|
Calculating feature variances of standardized and clipped values
0%   10   20   30   40   50   60   70   80   90   100%
[----|----|----|----|----|----|----|----|----|----|
**************************************************|
Error in rownames(st_data[[st_assay]]@data) : 
  no slot of name "data" for this object of class "Assay5"

I think the error is caused by Seurat v5 object's format change. This is the format of my object, which uses Seurat v5

The count and data are wrapped in layer object(?)/variable(?). I wonder if someone has a tool to downgrade Seurat object, since my preprocessing code didn't work on the latest v4...

p.s: Tried to just copy and paste the count and data outside the layer object(?)/variable(?), didn't work...

sessionInfo()

R version 4.3.2 (2023-10-31)
Platform: aarch64-unknown-linux-gnu (64-bit)
Running under: Ubuntu 22.04.3 LTS

Matrix products: default
BLAS:   /usr/lib/aarch64-linux-gnu/openblas-pthread/libblas.so.3 
LAPACK: /usr/lib/aarch64-linux-gnu/openblas-pthread/libopenblasp-r0.3.20.so;  LAPACK version 3.10.0

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C             LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

time zone: Asia/Jakarta
tzcode source: system (glibc)

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] ConsensusClusterPlus_1.66.0 viridis_0.6.4               viridisLite_0.4.2           Seurat_5.0.1               
[5] SeuratObject_5.0.1          sp_2.1-2                    dplyr_1.1.4                 CellTrek_0.0.94            

loaded via a namespace (and not attached):
  [1] RColorBrewer_1.1-3     rstudioapi_0.15.0      jsonlite_1.8.8         magrittr_2.0.3        
  [5] spatstat.utils_3.0-4   vctrs_0.6.5            ROCR_1.0-11            spatstat.explore_3.2-5
  [9] rstatix_0.7.2          htmltools_0.5.7        dynamicTreeCut_1.63-1  broom_1.0.5           
 [13] sctransform_0.4.1      parallelly_1.36.0      KernSmooth_2.23-22     htmlwidgets_1.6.4     
 [17] ica_1.0-3              plyr_1.8.9             plotly_4.10.3          zoo_1.8-12            
 [21] igraph_1.6.0           mime_0.12              lifecycle_1.0.4        pkgconfig_2.0.3       
 [25] Matrix_1.6-4           R6_2.5.1               fastmap_1.1.1          magic_1.6-1           
 [29] fitdistrplus_1.1-11    future_1.33.1          shiny_1.8.0            digest_0.6.33         
 [33] colorspace_2.1-0       patchwork_1.1.3        tensor_1.5             RSpectra_0.16-1       
 [37] irlba_2.3.5.1          akima_0.6-3.4          ggpubr_0.6.0           philentropy_0.8.0     
 [41] progressr_0.14.0       fansi_1.0.6            spatstat.sparse_3.0-3  httr_1.4.7            
 [45] polyclip_1.10-6        abind_1.4-5            compiler_4.3.2         backports_1.4.1       
 [49] carData_3.0-5          fastDummies_1.7.3      ggsignif_0.6.4         MASS_7.3-60           
 [53] tools_4.3.2            lmtest_0.9-40          httpuv_1.6.13          future.apply_1.11.1   
 [57] goftest_1.2-3          glue_1.6.2             dbscan_1.1-12          DiagrammeR_1.0.10     
 [61] nlme_3.1-163           promises_1.2.1         grid_4.3.2             Rtsne_0.17            
 [65] cluster_2.1.4          reshape2_1.4.4         generics_0.1.3         gtable_0.3.4          
 [69] spatstat.data_3.0-3    tidyr_1.3.0            data.table_1.14.10     car_3.1-2             
 [73] utf8_1.2.4             BiocGenerics_0.48.1    spatstat.geom_3.2-7    RcppAnnoy_0.0.21      
 [77] ggrepel_0.9.4          RANN_2.6.1             pillar_1.9.0           stringr_1.5.1         
 [81] spam_2.10-0            RcppHNSW_0.5.0         later_1.3.2            splines_4.3.2         
 [85] lattice_0.22-5         survival_3.5-7         deldir_2.0-2           tidyselect_1.2.0      
 [89] miniUI_0.1.1.1         pbapply_1.7-2          gridExtra_2.3          scattermore_1.2       
 [93] Biobase_2.62.0         matrixStats_1.2.0      visNetwork_2.1.2       stringi_1.8.3         
 [97] lazyeval_0.2.2         codetools_0.2-19       data.tree_1.1.0        tibble_3.2.1          
[101] packcircles_0.3.6      cli_3.6.2              uwot_0.1.16            geometry_0.4.7        
[105] xtable_1.8-4           reticulate_1.34.0      randomForestSRC_3.2.3  munsell_0.5.0         
[109] Rcpp_1.0.11            globals_0.16.2         spatstat.random_3.2-2  png_0.1-8             
[113] fastcluster_1.2.3      parallel_4.3.2         ellipsis_0.3.2         ggplot2_3.4.4         
[117] dotCall64_1.1-1        listenv_0.9.0          scales_1.3.0           ggridges_0.5.5        
[121] leiden_0.4.3.1         purrr_1.0.2            rlang_1.1.2            cowplot_1.1.2

Start at CellTrek::traint and search the package for rownames(st_data[[st_assay]]@data), using the reported Seurat 5.0.1 and SeuratObject 5.0.1 setup to reproduce the failure. Done means traint accepts the shown Seurat v5 object without the Assay5 data-slot error; no file or test is named in the issue.