Make sure that the inspected value is of type `dict`

def validate(self, value):
        """Make sure that the inspected value is of type `dict` """
        if not isinstance(value, dict):
            self.raise_error('Only Python dict may be used in the DictField vs provided {0}'
                             .format(type(value).__name__))
        super(DictField, self).validate(value)