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

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