re-add tree

.github/workflows/pr.yml

@@ -68,7 +68,7 @@ jobs:
           echo "training result directory missing" >&2 
           exit 1
         fi
-        # tree example
+        tree example
 
         dfpl predict -f example/predict.json
         if [ ! -d example/results_predict/ ]; then
@@ -80,14 +80,14 @@ jobs:
           echo "predict result should have at least 6 lines. But had only $(cat example/results_predict/smiles.csv | wc -l)" >&2 
           exit 1
         fi
-        # tree example
+        tree example
         
         dfpl traingnn -f example/traingnn.json
         if [ ! -d dmpnn-random/ ]; then
           echo "predict result directory missing" >&2 
           exit 1
         fi
-        # tree example
+        tree example
 
         dfpl predictgnn -f example/predictgnn.json
         if [ ! -d preds_dmpnn/ ]; then
@@ -100,5 +100,4 @@ jobs:
           exit 1
         fi
         
-        
         dfpl convert -f tests/data