Template for city

[ghost]

In the Brazil file I would like to see a generic class for city. This generic class can be instancied with a string parameter and according to this parameter we will instanciate some specific city class.
Example:

Class GenericCity():
  def __new__(cls, city: str):
          if city=='sp:
              return BrazilSaoPauloCity
          elif city =='rj'
             return BrazilRiodeJaneiroCity
          return super().__new__(cls)
  def __init__(cls):
     ....

city = GenericCity('sp')
city is a BrazilSaoPauloCity class.

@brunobord what do you think?
I can do a PR for this