import pandas as pd
from typing import List

def ensure_has_columns(df: pd.DataFrame, columns: List[str]):
    all_columns = columns
#    print("all_columns={}".format(all_columns))
#    print("df={}".format(df.columns.tolist()))
    for c in reversed(columns):
        if not c in df.columns.tolist():
          df.insert(0, column=c, value=pd.Series())
#    print("df={}".format(df.columns.tolist()))
    return df