On: Python stands to lose its GIL, and gain a lot of speed

[ynik]

Currently, dictionary updates are atomic only if the keys are primitive types.

`dict.update()` will call methods like `__eq__`, and those methods (if implemented in Python) may temporarily release the GIL.

[kzrdude → ynik]

Unfortunately the Python docs says that dict.update() is atomic. It's being fixed though... It came out during these discussions.