'Adjust the direction of the ticklabel.
ACCEPTS: [ "+" | "-" ]
Note that the label_direction \'+\' and \'-\' are relative to the
direction of the increasing coordinate.'

def set_ticklabel_direction(self, tick_direction):

    if (tick_direction not in [u'+', u'-']):
        raise ValueError(u'direction    must    be    one    of    "+",    "-"')
    if (tick_direction == u'-'):
        self._ticklabel_add_angle = 180
    else:
        self._ticklabel_add_angle = 0
