define check missing function

def check_missing(df, cut_off=0, sort=True):
    freq = df.isnull().sum()
    percent = df.isnull().sum() / df.shape[0] * 100
    types = df.dtypes
    unique = df.apply(pd.unique).to_frame(name='Unique Values')['Unique Values']
    unique_counts = df.nunique(dropna=False)
    df_miss = pd.DataFrame({
        'missing_percentage': percent,
        'missing_frequency': freq,
        'types': types,
        'count_value': unique_counts,
        'unique_values': unique
    })
    if sort:
        df_miss.sort_values(by='missing_frequency', ascending=False, inplace=True)
    return df_miss[df_miss['missing_percentage'] >= cut_off]