def calc_mode (df, nazwa_polutwa)

### START FUNCTION
def calc_mean_mode(df, column_name):
    numeric = df.select_dtypes(include=['int64', 'float64']).columns
    non_numeric = df.select_dtypes(include=['object']).columns

    if column_name in numeric:
        return round(np.mean(df[column_name]), 2)

    elif column_name in non_numeric:
        return sorted(list(df[column_name].value_counts().index[df[column_name].value_counts() == df[column_name].value_counts().max()]))

    else:
        raise ValueError


### END FUNCTION
Abayomi Briggs