I am getting thats kind of error Error in (function (classes, fdef, mtable) : unable to find an inherited method for function ‘upsetplot’ for signature ‘"NULL"’. Why 's that? This code what I am trying to run is getting the enrichment results by Over-Representation Analysis with ClusterProfiler.

organism = "org.Hs.eg.db"
#BiocManager::install(organism, character.only = TRUE)
library(organism, character.only = TRUE)


# reading in input from deseq2
df = read.csv("PT_vs_STN_DNM2.overexp.csv", header=TRUE)

# we want the log2 fold change 
original_gene_list <- df$log2FoldChange

# name the vector
names(original_gene_list) <- df$X

# omit any NA values 
gene_list<-na.omit(original_gene_list)

# sort the list in decreasing order (required for clusterProfiler)
gene_list = sort(gene_list, decreasing = TRUE)

# Exctract significant results (padj < 0.05)
sig_genes_df = subset(df, padj < 0.05)

# From significant results, we want to filter on log2fold change
genes <- sig_genes_df$log2FoldChange

# Name the vector
names(genes) <- sig_genes_df$X

# omit NA values
genes <- na.omit(genes)

# filter on min log2fold change (log2FoldChange > 2)
genes <- names(genes)[abs(genes) > 2]


go_enrich <- enrichGO(gene = genes,
                      universe = names(gene_list),
                      OrgDb = organism, 
                      keyType = 'ENSEMBL',
                      readable = T,
                      ont = "BP",
                      pvalueCutoff = 0.05, 
                      qvalueCutoff = 0.10)

#BiocManager::install("enrichplot")
library(enrichplot)
memory.limit(size=56000)
upsetplot(go_enrich)


# include your problematic code here with any corresponding output 
# please also include the results of running the following in an R session 

sessionInfo( )