/usr/lib/python2.7/dist-packages/google/protobuf/internal/ is in python-protobuf 2.5.0-9ubuntu1.
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/usr/lib/python2.7/dist-packages/google/protobuf/internal/__init__.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/api_implementation.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/containers.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/decoder.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/encoder.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/enum_type_wrapper.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/message_listener.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/python_message.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/type_checkers.py
/usr/lib/python2.7/dist-packages/google/protobuf/internal/wire_format.py