docs: def _getData(self, data):
          """ Check that data is acceptable and return it.
  
          Default behavior is that the data has to be of type `dict`. In derived
          classes this method could for example allow `None` or empty strings and
          just return empty dictionary.
  
          :raises: ``ValidationError`` if data is missing or wrong type
          :return: the data to be validated
          """
  
          if not isinstance(data, dict):
              raise ValidationError(
                  'data is not a valid dictionary: %s' % (str(type(data)),))
          return data