code: def _add_default_entries(input_dict, defaults_dict):
      for key, value in defaults_dict.iteritems():
          if key == 'patients':
              print('Cannot default `patients`.')
              continue
          if isinstance(value, dict):
              if key not in input_dict or input_dict[key] is None:
                  input_dict[key] = value
              else:
                  r = _add_default_entries(input_dict.get(key, {}), value)
                  input_dict[key] = r
          else:
              if key not in input_dict or input_dict[key] is None:
                  input_dict[key] = value
      return input_dict