It looks like Pandas has deprecated this method of indexing. According to their docs:
This behavior is deprecated and will show a warning message pointing
to this section. The recommended alternative is to use .reindex()
Using the new recommended method, you can filter your columns using:
tips_filtered = tips_df.reindex(columns = filtered_columns).
NB: To reindex rows, you would use reindex(index = ...) (More information here).