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diff --git a/src/mailman/interfaces/workflows.py b/src/mailman/interfaces/workflows.py
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+# Copyright (C) 2015-2017 by the Free Software Foundation, Inc.
+#
+# This file is part of GNU Mailman.
+#
+# GNU Mailman 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 3 of the License, or (at your option)
+# any later version.
+#
+# GNU Mailman 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
+# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Interfaces describing the a workflow, it's state and it's state manager."""
+
+from public import public
+from zope.interface import Attribute, Interface
+
+
+@public
+class IWorkflowState(Interface):
+    """The state of a workflow."""
+
+    token = Attribute('A unique key identifying the workflow instance.')
+
+    step = Attribute("This workflow's next step.")
+
+    data = Attribute('Additional data (may be JSON-encoded).')
+
+
+@public
+class IWorkflowStateManager(Interface):
+    """The workflow states manager."""
+
+    def save(token, step, data=None):
+        """Save the state of a workflow.
+
+        :param token: A unique token identifying this workflow instance.
+        :type token: str
+        :param step: The next step for this workflow.
+        :type step: str
+        :param data: Additional data (workflow-specific).
+        :type data: str
+        """
+
+    def restore(token):
+        """Get the saved state for a workflow or None if nothing was saved.
+
+        :param token: A unique token identifying this workflow instance.
+        :type token: str
+        :return: The saved state associated with this name/token pair, or None
+            if the pair isn't in the database.
+        :rtype: ``IWorkflowState``
+        """
+
+    def discard(token):
+        """Throw away the saved state for a workflow.
+
+        :param token: A unique token identifying this workflow instance.
+        :type token: str
+        """
+
+    count = Attribute('The number of saved workflows in the database.')
+
+
+@public
+class IWorkflow(Interface):
+    """A workflow."""
+
+    name = Attribute('The name of the workflow, must be unique.')
+    description = Attribute('A brief description of the workflow.')
+    initial_state = Attribute('The state in which the workflow starts.')
+    save_attributes = Attribute('The sequence of attributes of the workflow, '
+                                'which are saved.')
+
+    def __iter__():
+        """Return an iterator over the steps."""
+
+    def __next__():
+        """Run the next step from the queue.
+
+        :return: The result of the step run.
+        """
+
+    def push(step):
+        """Push a step to this workflows queue."""
+
+    def run_thru(stop_after):
+        """Run the state machine through and including the given step.
+
+        :param stop_after: Name of method, sans prefix to run the
+            state machine through.  In other words, the state machine runs
+            until the named method completes.
+        """
+
+    def run_until(stop_before):
+        """Run the state machine until (not including) the given step.
+
+        :param stop_before: Name of method, sans prefix that the
+            state machine is run until the method is reached.  Unlike
+            `run_thru()` the named method is not run.
+        """
+
+    def save():
+        """Save the workflow in it's current state.
+
+        Needs to have the `token` attribute set.
+        """
+
+    def restore():
+        """Restore the workflow from the database.
+
+        Needs to have the `token` attribute set.
+        """
+
+
+@public
+class ISubscriptionWorkflow(IWorkflow):
+    """A workflow used for subscription."""
+
+
+@public
+class IUnsubscriptionWorkflow(IWorkflow):
+    """A workflow used for unsubscription."""