* Reformat sdk only using the new yapf config.
* Reformat docstrings using docformatter.
* update golden files to resolve diff caused by whitespaces
* fix some tests
* format .py files under sdk/python/tests using yapf
* additional docformatter
* fix some tests
* Lint Python code for undefined names
* Lint Python code for undefined names
* Exclude tfdv.py to workaround an overzealous pytest
* Fixup for tfdv.py
* Fixup for tfdv.py
* Fixup for tfdv.py