code: def sanitize_dict(input_dict):
      r
      plain_dict = dict()
      for key in input_dict.keys():
          value = input_dict[key]
          if hasattr(value, 'keys'):
              plain_dict[key] = sanitize_dict(value)
          else:
              plain_dict[key] = value
      return plain_dict
docs: r"""
      Given a nested dictionary, ensures that all nested dicts are normal
      Python dicts.  This is necessary for pickling, or just converting
      an 'auto-vivifying' dict to something that acts normal.