[Hot fix][Dataset] knowledge graph dataset statistics output (#1952)

* Hot fix

* Fix
Co-authored-by: Ubuntu <ubuntu@ip-172-31-51-214.ec2.internal>

python/dgl/data/knowledge_graph.py

@@ -75,9 +75,9 @@ class KnowledgeGraphDataset(DGLBuiltinDataset):
         if self.verbose:
             print("# entities: {}".format(num_nodes))
             print("# relations: {}".format(num_rels))
-            print("# training edges: {}".format(len(train)))
-            print("# validation edges: {}".format(len(valid)))
-            print("# testing edges: {}".format(len(test)))
+            print("# training edges: {}".format(train.shape[0]))
+            print("# validation edges: {}".format(valid.shape[0]))
+            print("# testing edges: {}".format(test.shape[0]))
 
         # for compatability
         self._train = train
@@ -166,9 +166,9 @@ class KnowledgeGraphDataset(DGLBuiltinDataset):
         if self.verbose:
             print("# entities: {}".format(self.num_nodes))
             print("# relations: {}".format(self.num_rels))
-            print("# training edges: {}".format(len(train_idx)))
-            print("# validation edges: {}".format(len(valid_idx)))
-            print("# testing edges: {}".format(len(test_idx)))
+            print("# training edges: {}".format(train_idx.shape[0]))
+            print("# validation edges: {}".format(valid_idx.shape[0]))
+            print("# testing edges: {}".format(test_idx.shape[0]))
 
     @property
     def num_nodes(self):