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diff --git a/src/python/_framework/foundation/stream.py b/src/python/_framework/foundation/stream.py
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+++ b/src/python/_framework/foundation/stream.py
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+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Interfaces related to streams of values or objects."""
+
+import abc
+
+
+class Consumer(object):
+  """Interface for consumers of finite streams of values or objects."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def consume(self, value):
+    """Accepts a value.
+
+    Args:
+      value: Any value accepted by this Consumer.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def terminate(self):
+    """Indicates to this Consumer that no more values will be supplied."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def consume_and_terminate(self, value):
+    """Supplies a value and signals that no more values will be supplied.
+
+    Args:
+      value: Any value accepted by this Consumer.
+    """
+    raise NotImplementedError()