Returns the values for this dataset.
        
        :return     [{<str> axis: <variant> value, ..}, ..]

def values(self, axis=None):
        """
        Returns the values for this dataset.
        
        :return     [{<str> axis: <variant> value, ..}, ..]
        """
        if axis is None:
            return self._plot
        else:
            return [value.get(axis) for value in self._plot]