write_csv has unexpected behavior and possibly inaccurate docs

[EthanGoldman]

The API docs for write_csv() don't explain what the header parameter is used for (if True, it includes column headers in the output file, which is pretty standard for a csv file) or that it defaults to False. The API docs say it's an object that defaults to None, but doesn't list valid inputs. It seems to be a bool that defaults to False.

Looking over the other API docs, most of the parameters are not adequately documented, either.