Fix num_labels to num_classes in dataset files (#6666)

python/dgl/data/ppi.py

@@ -59,7 +59,7 @@ class PPIDataset(DGLBuiltinDataset):
     Examples
     --------
     >>> dataset = PPIDataset(mode='valid')
-    >>> num_labels = dataset.num_labels
+    >>> num_classes = dataset.num_classes
     >>> for g in dataset:
     ....    feat = g.ndata['feat']
     ....    label = g.ndata['label']
@@ -173,6 +173,10 @@ class PPIDataset(DGLBuiltinDataset):
     def num_labels(self):
         return 121
 
+    @property
+    def num_classes(self):
+        return 121
+
     def __len__(self):
         """Return number of samples in this dataset."""
         return len(self.graphs)

python/dgl/data/qm7b.py

@@ -141,6 +141,11 @@ class QM7bDataset(DGLDataset):
         """Number of prediction tasks."""
         return 14
 
+    @property
+    def num_classes(self):
+        """Number of prediction tasks."""
+        return 14
+
     def __getitem__(self, idx):
         r"""Get graph and label by index
 

python/dgl/data/qm9.py

@@ -157,6 +157,16 @@ class QM9Dataset(DGLDataset):
         """
         return self.label.shape[1]
 
+    @property
+    def num_classes(self):
+        r"""
+        Returns
+        --------
+        int
+            Number of prediction tasks.
+        """
+        return self.label.shape[1]
+
     @property
     def num_tasks(self):
         r"""