Added the doc to the __init__ in data_folder, to fix the sphinx warning

bob/learn/pytorch/datasets/data_folder.py

@@ -147,6 +147,48 @@ class DataFolder(data.Dataset):
                  purposes=['real', 'attack'],
                  allow_missing_files = True,
                  **kwargs):
+        """
+        Attributes
+        ----------
+
+        data_folder : str
+            A directory containing the training data.
+
+        transform : callable
+            A function/transform that  takes in a PIL image, and returns a
+            transformed version. E.g, ``transforms.RandomCrop``. Default: None.
+
+        extension : str
+            Extension of the data files. Default: ".hdf5".
+            Note: this is the only extension supported at the moment.
+
+        bob_hldi_instance : object
+            An instance of the HLDI interface. Only HLDI's of bob.pad.face
+            are currently supported.
+
+        hldi_type : str
+            String defining the type of the HLDI. Default: "pad".
+            Note: this is the only option currently supported.
+
+        groups : str or [str]
+            The groups for which the clients should be returned.
+            Usually, groups are one or more elements of ['train', 'dev', 'eval'].
+            Default: ['train', 'dev', 'eval'].
+
+        protocol : str
+            The protocol for which the clients should be retrieved.
+            Default: 'grandtest'.
+
+        purposes : str or [str]
+            The purposes for which File objects should be retrieved.
+            Usually it is either 'real' or 'attack'.
+            Default: ['real', 'attack'].
+
+        allow_missing_files : bool
+            The missing files in the ``data_folder`` will not break the
+            execution if set to True.
+            Default: True.
+        """
 
         self.data_folder = data_folder
         self.transform = transform
@@ -239,8 +281,8 @@ class DataFolder(data.Dataset):
     #==========================================================================
     def __len__(self):
         """
-        Attributes
-        ----------
+        Returns
+        -------
 
         len : int
             The length of the file list.