minor error fix

app.py

@@ -45,7 +45,7 @@ df = df[['Serial Number', "author", "Total Usage", "models", "datasets", "spaces
 df = df.sort_values(by='Total Usage', ascending=False)
 
 naturalsize_columns = ['Total Usage', 'models', 'datasets', 'spaces']
-df[cols_to_naturalsize] = df[naturalsize_columns].applymap(naturalsize)
+df[naturalsize_columns] = df[naturalsize_columns].applymap(naturalsize)
 
 df = apply_headers(df, ["🔢 Serial Number", "👤 Author", "⚡️ Total Usage", "🏛️ Models", "📊 Datasets", "🚀 Spaces"])