code: def cast_dicts(self, to=DEFAULT, d=DEFAULT):
          
          if to is DEFAULT:
              to = type(self)
          if d is DEFAULT:
              d = self
          if isinstance(d, list):
              return [v for v in (self.cast_dicts(to, v) for v in d)]
          elif isinstance(d, dict):
              return to({k: v for k, v in ((k, self.cast_dicts(to, v)) for k, v in d.items())})
          return d
docs: Returns a copy of d with all dicts casted to the type 'to'.