ชื่อของประเทศใดที่มีทั้งภาษาอังกฤษและฝรั่งเศสเป็นภาษาราชการ?
What are the names of nations where both English and French are official languages?
countrylanguage = pd.DataFrame(columns=['CountryCode', 'Language', 'IsOfficial']); country = pd.DataFrame(columns=['Name', 'Code'])
country[country['Code'].isin(countrylanguage[(countrylanguage['Language'] == 'English') & (countrylanguage['IsOfficial'] == 'T')]['CountryCode']) & country['Code'].isin(countrylanguage[(countrylanguage['Language'] == 'French') & (countrylanguage['IsOfficial'] == 'T')]['CountryCode'])]['Name']