How to fix 'DataFrame' object is not callable' error?

Question

Python

Hey!

When I iterate over the dataframe, I get the following error:
TypeError: 'DataFrame' object is not callable

In the code, I check if a numeric value is entered in a cell. Empty cell allowed

def read_file_to_df(file):
    data = pd.read_excel(file)

    for index, row in data.iterrows():
        if row["Оценка"] is not None and type(row["Оценка"]) != float:
            raise ValueError(_("Упс... Строка {} столбца Оценка должна содержать число или быть пустой!").format(index + 2))

    return data

Tell me, what is the reason for the error?