we don't support start, stop kwds in Sparse

def validate_read(self, kwargs):
        """
        we don't support start, stop kwds in Sparse
        """
        kwargs = super().validate_read(kwargs)
        if 'start' in kwargs or 'stop' in kwargs:
            raise NotImplementedError("start and/or stop are not supported "
                                      "in fixed Sparse reading")
        return kwargs