import pandas as pd
import numpy as np

table = pd.DataFrame({"note":pd.Series(["covered", None], dtype="string"), "kg":[12., np.nan]})
result = table.assign(note_missing=table["note"].isna(), note=table["note"].fillna("No note supplied"))
print(result["note"].tolist())
print(result["note_missing"].tolist())
print(result["kg"].isna().tolist())