mypaint 
Traceback (most recent call last):
  File "/usr/bin/mypaint", line 123, in <module>
    from gui import main
  File "/usr/share/mypaint/gui/main.py", line 15, in <module>
    from gui import application
  File "/usr/share/mypaint/gui/application.py", line 14, in <module>
    import filehandling, keyboard, brushmanager
  File "/usr/share/mypaint/gui/filehandling.py", line 17, in <module>
    from lib import document, helpers
  File "/usr/share/mypaint/lib/document.py", line 17, in <module>
    import command, stroke, layer
  File "/usr/share/mypaint/lib/command.py", line 9, in <module>
    import layer
  File "/usr/share/mypaint/lib/layer.py", line 11, in <module>
    import tiledsurface, strokemap, strokemap_pb2
  File "/usr/share/mypaint/lib/strokemap.py", line 13, in <module>
    import tiledsurface, idletask, strokemap_pb2
  File "/usr/share/mypaint/lib/strokemap_pb2.py", line 10, in <module>
    DESCRIPTOR = descriptor.FileDescriptor(
AttributeError: 'module' object has no attribute 'FileDescriptor'