Seebelow.

importpandasaspddata= {"Column2": [10,20,30],"Column3": ["A","B","C"],"Column4": ["Lala","YesYes","NoNo"],}df1=pd.DataFrame(data)

importpolarsaspldata= {"Column1": ["Text1","Text2","Text3"],"Column2": [10,20,30],"Column3": ["A","B","C"]}df2=pl.DataFrame(data)

result=df1.join(df2,on=["Column2","Column3"],how="inner")

---------------------------------------------------------------------------ValueError                                Traceback (most recent call last)~\AppData\Local\Temp\ipykernel_11612\367032622.pyin?()----> 1 result = df1.join(df2, on=["Column2","Column3"], how="inner")c:\Users\name\AppData\Local\Programs\Python\Python312\Lib\site-packages\pandas\core\frame.pyin?(self, other, on, how, lsuffix, rsuffix, sort, validate)  10766                 validate=validate,  10767             )  10768         else:  10769if on is not None:> 10770                 raise ValueError(  10771"Joining multiple DataFrames only supported for joining on index"  10772                 )  10773 ValueError: Joining multiple DataFrames only supportedfor joining on index