code: def _clean_dict(in_dict):
      
      out = {}
      for key, value in iteritems(in_dict):
          if isinstance(value, dict):
              value = _clean_dict(value)
          if value is None:
              continue
          out[key] = value
      return out
docs: Recursively remove None-valued items from dict.
      :param in_dict:
      :return: