====city that is a city====
Select distinct city records in ptoassigneend_us_extracted and store them in ptoasigneend_us_citylist ptoassigneend_us_citylist (775). Since the city list is not long, I briefly cleaned the list by hand, and still stored in ptoassigneend_us_citylist (730).
The safest method to identify clean city is to find records with feature city in ptoassigneend_us_citylist.