How to output Fragment file with some specific cells？

[capuddddd]

i have extracted some subtype cells dataset, how to output fragments file of this group of cells?

sc
An object of class Seurat 
198759 features across 24101 samples within 3 assays 
Active assay: chromvar (2346 features, 0 variable features)
 1 layer present: data
 2 other assays present: peaks, RNA
 3 dimensional reductions calculated: lsi, harmony, umap
> fragments
[[1]]
A Fragment object for 1336 cells
[[2]]
A Fragment object for 3589 cells
[[3]]
A Fragment object for 4043 cells
[[4]]
A Fragment object for 6261 cells
[[5]]
A Fragment object for 3652 cells
[[6]]
A Fragment object for 4431 cells
[[7]]
A Fragment object for 789 cells