In this PR there was a change in how `DateType` is being returned to users (line 1968 in dataframe.py). This can cause client code to fail, as in the following example from a python terminal:
Above we show both the old behavior (returning an "object" col) and the new behavior (returning a datetime column). Since there may be user code relying on the old behavior, I'd suggest reverting this specific part of this change. Also note that the NOTE on the docstring for the "_to_corrected_pandas_type" seems to be off, referring to the old behavior and not the current one.