Looks up an axis for this chart by the given name.
        
        :return     <projexui.widgets.xchart.XChartAxis> || None

def axis(self, name):
        """
        Looks up an axis for this chart by the given name.
        
        :return     <projexui.widgets.xchart.XChartAxis> || None
        """
        for axis in self.axes():
            if axis.name() == name:
                return axis
        return None