ch02_basics/types.py causing Jupyter Notebook kernel to crash ["Fix" included] #23

Hi,

Just a heads up - the types.py is causing Jupyter Notebook's kernel to crash when attempting to load any of the ipynb notebooks:

(Snipped stacktrace)
...
File "~/opt/anaconda3/lib/python3.5/functools.py", line 22, in
from types import MappingProxyType
File "~/DEEP_LEARNING/research/TensorFlow-Book/ch02_basics/types.py", line 3, in
...

Fix: renaming types.py to types_examples.py (or any non site-package/standard lib name) fixes the issue.

Hope that helps!