docs: def subclass(cls, vt_code, vt_args):
          """Return a dynamic subclass that has the extra parameters built in"""
          from geoid import get_class
          import geoid.census
  
          parser = get_class(geoid.census, vt_args.strip('/')).parse
  
          cls = type(vt_code.replace('/', '_'), (cls,), {'vt_code': vt_code, 'parser': parser})
          globals()[cls.__name__] = cls
          assert cls.parser
  
          return cls