FEATURE: Type hints for DataFrame, Series, etc.
#### Is your feature request related to a problem?

Type hinting with `pd.DataFrame` and `pd.Series` (`def data_science_etl_function(input_data_frame: pd.DataFrame) -> pd.DataFrame:`) does not document ETL APIs build on top of `pandas` w.r.t. `DataFrame` and/or `Series` meta-data like shape, indices, etc.

#### Describe the solution you'd like

It would be great to have something like [`nptyping`](https://github.com/ramonhagenaars/nptyping) (type hints for numpy data types) for `pd.DataFrames` and `pd.Series`.

#### API breaking implications

Should not break the API.

#### Describe alternatives you've considered

There is no real workaround. Adding `docstrings` everywhere is anoying and people tend to write them in an incomplete manner or miss them completly. Extensive unit testing of functionality :dizzy_face: