Correct the code to correctly output the dataframe with this data: gdpdiff = pd.DataFrame({'Top1': df19[['Country or region', 'GDP per capita']]\ .sort_values(by='GDP per capita', ascending=False).head(20)[0:1], 'Top20': df19[['Country or region', 'GDP per capita']]\ .sort_values(by='GDP per capita', ascending=False).head(20)[19:20]}) gdpdiff

def top20(df):
    gdpdiff = pd.DataFrame({'Top1': df[['Country or region', 'GDP per capita']]\
                                .sort_values(by='GDP per capita', ascending=False).head(20)[0:1],
                           'Top20': df[['Country or region', 'GDP per capita']]\
                                .sort_values(by='GDP per capita', ascending=False).head(20)[19:20]})
    return gdpdiff
    
top20(df19)