pd.DataFrame.duplicated, drop_duplicates does not support column operation
I was trying to use .duplicated to find identical columns, and possibly dropping them, but realized it doesn't do columnar operations.
It would be great if pd.DataFrame.duplicated or pd.DataFrame.drop_duplicates supports axis= argument. 

Current version 0.25.3 not supporting axis=
https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.duplicated.html

Some workaround by custom function
https://thispointer.com/how-to-find-drop-duplicate-columns-in-a-dataframe-python-pandas/

