title: How to writeback to dataframe using transform_df in palantir foundry?
body: <p>I created a library for updating description of the columns of the input dataset. This function takes three parameter as input (input_dataset, output_dataset,  config file) and eventually writes back the description of output dataset. So now we want to import this library across various use cases. How to go for those cases where we are writing spark transformation i.e taking inputs through transform_df because here we can't assign output to output variable. In that situation how can i call  my description library function? How to proceed in those situation in palantir foundry. Any suggestions?</p>