diff --git a/bob/pad/base/database/file.py b/bob/pad/base/database/file.py
index 2c1a2fd44159cfbe46fe778017654fd1eed7e5fb..7663cf85f4031304d50add4c35640bc4f71d2208 100644
--- a/bob/pad/base/database/file.py
+++ b/bob/pad/base/database/file.py
@@ -4,10 +4,9 @@
 # @date:   Wed May 18 10:09:22 CET 2016
 #
 
-from bob.bio.base.database import BioFile
+import bob.bio.base.database
 
-
-class PadFile(BioFile):
+class PadFile(bob.bio.base.database.BioFile):
     """A simple base class that defines basic properties of File object for the use in PAD experiments"""
 
     def __init__(self, client_id, path, attack_type=None, file_id=None):
diff --git a/bob/pad/base/database/filelist/query.py b/bob/pad/base/database/filelist/query.py
index f1191af6face2ba5d9be290295e09d644ce5c744..14935dfb0b81d693b26e124fe6c06bb0090de674 100644
--- a/bob/pad/base/database/filelist/query.py
+++ b/bob/pad/base/database/filelist/query.py
@@ -219,7 +219,7 @@ class FileListPadDatabase(FileListBioDatabase, PadDatabase):
         return self.__client_id_list__(groups, 'for_real', protocol)
 
     def objects(self, groups=None, protocol=None, purposes=None, model_ids=None, **kwargs):
-        """Returns a set of :py:class:`File` objects for the specific query by the user.
+        """Returns a set of :py:class:`PadFile` objects for the specific query by the user.
 
         Keyword Parameters:
 
@@ -239,7 +239,7 @@ class FileListPadDatabase(FileListBioDatabase, PadDatabase):
         model_ids : [various type]
           This parameter is not supported in PAD databases yet
 
-        Returns: A list of :py:class:`File` objects considering all the filtering criteria.
+        Returns: A list of :py:class:`PadFile` objects considering all the filtering criteria.
         """
 
         purposes = self.check_parameters_for_validity(purposes, "purpose", ('real', 'attack'))
@@ -273,3 +273,9 @@ class FileListPadDatabase(FileListBioDatabase, PadDatabase):
 
     def annotations(self, file):
         return super(FileListPadDatabase, self).annotations(file)
+
+    def tobjects(self, groups=None, protocol=None, model_ids=None, **kwargs):
+        pass
+
+    def zobjects(self, groups=None, protocol=None, **kwargs):
+        pass
diff --git a/doc/extra-intersphinx.txt b/doc/extra-intersphinx.txt
index 4923eada34c5fbf0d119b5319ff9178ad7c1a4ff..8adfb6781fe99dce201b91f1fc375e22db2e474e 100644
--- a/doc/extra-intersphinx.txt
+++ b/doc/extra-intersphinx.txt
@@ -3,4 +3,5 @@ numpy
 bob.bio.spear
 gridtk
 bob.db.base
-bob.db.avspoof
\ No newline at end of file
+bob.db.avspoof
+bob.bio.base
\ No newline at end of file