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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def df_names_to_idx(names:IntsOrStrs, df:DataFrame):
    "Return the column indexes of `names` in `df`."
    if not is_listy(names): names = [names]
    if isinstance(names[0], int): return names
    return [df.columns.get_loc(c) for c in names]