ประเภทบริการที่มีทั้งผลิตภัณฑ์ภาพถ่ายและผลิตภัณฑ์ฟิล์มมีคำอธิบายอะไรบ้าง?
What is the description of the service type which offers both the photo product and the film product?
ref_service_types = pd.DataFrame(columns=['Service_Type_Description', 'Service_Type_Code']); services = pd.DataFrame(columns=['Service_Type_Code', 'Product_Name'])
set(pd.merge(ref_service_types, services[services['Product_Name']=='photo'], on='Service_Type_Code')['Service_Type_Description']).intersection(pd.merge(ref_service_types, services[services['Product_Name']=='film'], on='Service_Type_Code')['Service_Type_Description'])