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 df_gdp_diff(df):
  df19 = df_19[df_19['Year'] == 2019]
  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]})
  return gdpdiff