I have a list (markers.l) of dataframes. Each dataframe denotes to one cluster. I try the following function to get the list of top 10 markers.

# Extract top 10 markers per cluster
top10 <- markers.l %>% 
  mutate(avg_fc = (Sample1_avg_log2FC + Sample2_avg_log2FC) /2) %>% 
  group_by(cluster_id) %>% 
  top_n(n = 10, 
        wt = avg_2fc)

# Visualize top 10 markers per cluster
View(top10)

Error in UseMethod("mutate"): no applicable method for 'mutate' applied to an object of class "list"
Traceback:

1. markers.l %>% mutate(avg_fc = (Sample1_avg_logFC + Sample2_avg_logFC)/2) %>% 
 .     group_by(cluster_id) %>% top_n(n = 10, wt = avg_fc)
2. top_n(., n = 10, wt = avg_fc)
3. filter(x, top_n_rank({
 .     {
 .         n
 .     }
 . }, !!wt))
4. group_by(., cluster_id)
5. mutate(., avg_fc = (Sample1_avg_logFC + Sample2_avg_logFC)/2)