pydata/pandas — pull request #8220 by onesandzeroes (2014-09-09 09:08:06+00:00)
Title: API: Series.to_csv(path=None) should return string to match DataFrame.to_csv()

Addresses #8215. Currently, `Series.to_csv(path=None)` returns `None`. The `DataFrame` method returns a string, and already had this behaviour mentioned in the docstring, so it should be OK to make the `Series` method match this.