fix topic assignment

app.py

@@ -356,7 +356,7 @@ def assignTopic(l):
     for x in l:
         topics.append(x[0])
 
-def topic_assignment():
+def topic_assignment(df):
     lda_topics = lda_model_final.show_topics(num_words=10)
 
     topics = []
@@ -515,7 +515,7 @@ def main(dataset, model):
     if model == 'LDA':
         base_lda()
         coherence = hyperparameter_optimization()
-        topic_assignment()
+        topic_assignment(df)
     else:
         base_bertopic()
         optimized_bertopic()