'Set the label position (top or bottom)
ACCEPTS: [ \'top\' | \'bottom\' ]'

def set_label_position(self, position):

    if (position == u'top'):
        self.label.set_verticalalignment(u'baseline')
    elif (position == u'bottom'):
        self.label.set_verticalalignment(u'top')
    else:
        msg = u"Position    accepts    only    [    'top'    |    'bottom'    ]"
        raise ValueError(msg)
    self.label_position = position
    self.stale = True
