diff --git a/product/ERP5/interfaces/granulatable.py b/product/ERP5/interfaces/granulatable.py
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+++ b/product/ERP5/interfaces/granulatable.py
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+# -*- coding: utf-8 -*-
+##############################################################################
+#
+# Copyright (c) 2009 Nexedi SA and Contributors. All Rights Reserved.
+#                    Jean-Paul Smets-Solanes <jp@nexedi.com>
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsability of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# garantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# 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.
+#
+##############################################################################
+
+from zope.interface import Interface
+
+class IGranulatable(Interface):
+  """
+  Convertable interface specification
+
+  Documents which implement IGranulatable can be analysed
+  and granulated into smaller sub documents. Reversely,
+  content can be updated from sub content.
+  """
+
+  def granulateContent():
+    """
+    Populates the current document with subcontent based on the
+    document content. This can be used for example to transform the
+    whole XML of an RSS feed into a collection of subcontents,
+    one per news item.
+
+    NOTE: this method used to be called populateContent
+    """
+
+  def assembleContent():
+    """
+    Updated the current document by assembling subcontent
+    and generate a new document. It is the reverse method
+    of IGranulatable.granulateContent
+    """
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