fillna in the cli-convert tutorial leads to
FutureWarning: Downcasting object dtype arrays on .fillna, .ffill, .bfill is deprecated and will change in a future version. Call result.infer_objects(copy=False) instead. To opt-in to the future behavior, set pd.set_option('future.no_silent_downcasting', True)
in the newer versions.
fillna in the cli-convert tutorial leads to
in the newer versions.