Update app.py

app.py

@@ -1,7 +1,8 @@
 import os,sys
 
 # install required packages
-os.system('pip install plotly')  # plotly 설치 추가
+os.system('pip install plotly')  # plotly 설치
+os.system('pip install matplotlib')  # matplotlib 설치
 os.system('pip install dgl==1.0.2+cu116 -f https://data.dgl.ai/wheels/cu116/repo.html')
 os.environ["DGLBACKEND"] = "pytorch"
 print('Modules installed')