def wb_clean(wb):
    """
    Clean the world bank data.
    Rename countries to match energy data set.
    """
    wb['Country Name'] = (wb['Country Name'].str
                          .replace('Korea, Rep.', 'South Korea'))
    wb['Country Name'] = (wb['Country Name'].str
                          .replace('Iran, Islamic Rep.', 'Iran'))
    wb['Country Name'] = (wb['Country Name'].str
                          .replace('Hong Kong SAR, China', 'Hong Kong'))
    wb = wb.set_index('Country Name')
    return(wb)