keep consistency in calling to_csv either dataframe or series

[FrankMN]

When I call to_csv of dataframe object, I am not required to explicitly set path parameter. The default one is None and will return a string. I thought the same thing for series object. This time the path parameter becomes explicitly required. I wonder if it is better to keep consistency between them.

[jreback]

Can u show an explicit example and pd.show_versions()

[gfyoung]

@jreback : There is no need. @FrankMN is referring to a signature mismatch, which you can see here and here. IMO we should default path=None for Series. This shouldn't be a breaking API change.