diff --git a/cybertools/integrator/base.py b/cybertools/integrator/base.py
index 98be980..11fac4f 100644
--- a/cybertools/integrator/base.py
+++ b/cybertools/integrator/base.py
@@ -1,34 +1,15 @@
-#
-#  Copyright (c) 2010 Helmut Merz helmutm@cy55.de
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, write to the Free Software
-#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
+# cybertools.util.integrator.base
 
-"""
-Base implementation for accessing external content objects.
-
-$Id$
+""" Base implementation for accessing external content objects.
 """
 
 import mimetypes
 import os
-from urllib import urlencode
+from urllib.parse import urlencode
 from zope.app.container.contained import Contained
 from zope.cachedescriptors.property import Lazy
 from zope import component
-from zope.interface import implements
+from zope.interface import implementer
 
 from cybertools.integrator.interfaces import IContainerFactory
 from cybertools.integrator.interfaces import IItemFactory, IFileFactory
@@ -61,10 +42,9 @@ class ProxyBase(object):
         return self.address.rsplit(os.path.sep, 1)[-1]
 
 
+@implementer(IReadContainer)
 class ReadContainer(ProxyBase, Contained):
 
-    implements(IReadContainer)
-
     icon = 'folder'
 
     @Lazy
@@ -112,18 +92,16 @@ class ReadContainer(ProxyBase, Contained):
     has_key = __contains__
 
 
+@implementer(IItem)
 class Item(ProxyBase, object):
 
-    implements(IItem)
-
     icon = 'item'
     __parent__ = None
 
 
+@implementer(IFile)
 class File(Item):
 
-    implements(IFile)
-
     def __init__(self, address, contentType, **kw):
         super(File, self).__init__(address, **kw)
         self.contentType = contentType
@@ -141,10 +119,9 @@ class File(Item):
         return (mimeTypes.get(self.contentType) or ['unknown'])[0]
 
 
+@implementer(IImage)
 class Image(File):
 
-    implements(IImage)
-
     icon = 'image'
 
     def getImageSize(self):
@@ -174,24 +151,21 @@ class Factory(object):
         return self.proxyClass(address, **kw)
 
 
+@implementer(IContainerFactory)
 class ContainerFactory(Factory):
 
-    implements(IContainerFactory)
-
     proxyClass = ReadContainer
 
 
+@implementer(IItemFactory)
 class ItemFactory(Factory):
 
-    implements(IItemFactory)
-
     proxyClass = Item
 
 
+@implementer(IFileFactory)
 class FileFactory(Factory):
 
-    implements(IFileFactory)
-
     proxyClass = File   # real implementations should also care about images
 
 
diff --git a/cybertools/integrator/filesystem.py b/cybertools/integrator/filesystem.py
index 962300d..33a306f 100644
--- a/cybertools/integrator/filesystem.py
+++ b/cybertools/integrator/filesystem.py
@@ -1,23 +1,6 @@
-#
-#  Copyright (c) 2012 Helmut Merz helmutm@cy55.de
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, write to the Free Software
-#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
+# cybertools.util.integrator.filesystem
 
-"""
-Access to objects in the file system.
+""" Access to objects in the file system.
 """
 
 import os, stat
@@ -26,7 +9,7 @@ from zope import component
 from zope.app.file.image import getImageInfo
 from zope.cachedescriptors.property import Lazy
 from zope.contenttype import guess_content_type
-from zope.interface import implements, Attribute
+from zope.interface import Attribute
 
 from cybertools.integrator.base import ContainerFactory, FileFactory
 from cybertools.integrator.base import ReadContainer, File, Image
diff --git a/cybertools/integrator/filesystem.txt b/cybertools/integrator/filesystem.txt
index aa05f6a..655b5cd 100644
--- a/cybertools/integrator/filesystem.txt
+++ b/cybertools/integrator/filesystem.txt
@@ -4,8 +4,6 @@ Integrating objects from external systems
 
 Integration of external sources.
 
-  ($Id$)
-
 
 Getting started
 ===============
@@ -101,7 +99,7 @@ A file object has additional attributes/methods.
   'index.html'
   >>> html.contentType
   'text/html'
-  >>> print html.data
+  >>> print(html.data.decode('UTF-8'))
   <html>...
       <img src="sub/loops_logo.png" />
       <a href="sub">Subdirectory</a>
diff --git a/pyproject.toml b/pyproject.toml
index f331949..d84f2c6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,6 +18,7 @@ dependencies = [
 	"persistent",
 	"pillow",
 	"zope.app.container",
+	"zope.app.file",
 	"zope.app.rotterdam",
 	"zope.app.testing",
 	"zope.authentication",